Oxide Materials Towards a Matured Post-silicon Electronics Era
FRAUNHOFER GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
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Frixos Stavrou (Mr.)
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Grant agreement ID: 246334
1 October 2010
30 September 2014
€ 13 355 499,38
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FRAUNHOFER GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Oxides for flexible, transparent electronics
Grant agreement ID: 246334
1 October 2010
30 September 2014
€ 13 355 499,38
€ 9 742 506
FRAUNHOFER GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
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Final Report Summary - ORAMA (Oxide Materials Towards a Matured Post-silicon Electronics Era)
In this summary we would like to give you a brief inside look in to the EU funded project titled “Oxide Materials Towards a Matured Post-silicon Electronics Era”, short abbreviation ORAMA. The name ORAMA has its origins from the Greek language όραμα, which means vision. This is exactly the vision driving the researchers working in this project to create a world with higher living comforts with the use of smarter materials. With the technological boost of the last century and the beginning of the new century more and more human machine interfaces arise to realize these dreams. Nevertheless we have to take care of our planet. Thus sustainability is an important factor to solve our future problems and in order to achieve this target, we need to minimize the power consumption. Therefore ORAMA works on oxide electronics as the enabling technology for the next generation of the electronics industry. One vision is to develop low cost flexible electronics for example wearable sensors, more efficient light sources as well as transparent displays. Currently, the large area electronics industry is subject to change of paradigms since the well-known processes for thin film silicon TFTs are partly substituted by better performing and easier to produce oxide TFTs. Such TFTs are for example the enabling technology for cost effective and high performance active matrix OLED displays. However, such breakthroughs are just the starting point for oxide electronics. Oxides allow for transparent devices which will be produced by patterned deposition on flexible substrates at low temperatures and also on large areas.
To realize this potential, we have utilized a holistic approach within our ORAMA project where the experimental R&D work on materials certified for applications in LED lighting, displays electronics and chemical sensing is supported by oxide materials and processes modeling on multiple scales. For example in LED processing a transparent conductive metal oxide is necessary on top of the LED. Simulations have made the fact comprehensible which helped us understand how to reach a process control without inducing a defect on the sensitive semiconductor. The simulation is a very important starting point with modelling of electronic band-structures, doping mechanisms, optical properties of crystalline or amorphous TCOs (Transparent Conductive Oxides) and ASOs (Amorphous Oxide Semiconductors) materials. Additionally a heuristic model for the thin-film morphology prediction of thin oxide films deposited by plasma processes was developed. And also a statistical Particle-in-Cell Monte-Carlo (PICMC) simulation of the growth of thin oxide films by plasma processes was performed. Further, device modellings of electrical circuits were applied for obtaining optimized circuit layouts. The materials development has been focused on both TCOs and ASOs ranging from binary to ternary and quaternary structures with the state of the art PVD, CVD and wet chemical processes. And also the non-conventional techniques like ink jet printing to overcome subtractive processes (e. g. lithography and etching) by additive processes.
The project is highlighted primarily in the form of three prototypes that were developed collaboratively in order to tangibly demonstrate how the newly developed materials can be implemented in different industrial fields and products. Those are:
1. Steering wheel application with displays and reconfigurable icons
2. Multifunctional glazing
3. p-type gas sensors
However, one of the primary objectives from the beginning was to prepare post-silicon era and oxide-based materials for application in optoelectronics and chemical sensing, consequently enabling European industry prepare for next-generation products. The above-mentioned demonstrators on the one hand help in identifying the potential contained in material development and on the other function as a “show and tell” device for communicating project results to a wider community."
Project Context and Objectives:
ORAMA presents a holistic approach to model, synthesize, characterize and certify oxides for electronic applications to overcome the limits of silicon based electronics and to bring the electronics industry into a new era of growth. It aims towards new classes of materials, the p- and n-type Active Semiconductor Oxides (ASO), passive n-type amorphous Transparent Conducting Oxides (a-TCOs) and p-n type junctions based on the above. These materials will be certified for device concepts highlighting the potential of oxides as electronic materials in the automotive and lighting industry. This is a strongly competitive environment of high importance for Europe’s economy and with challenging demands on information technology such as sensors, displays and energy sources to provide sustainable mobility for the European society.
ORAMA develops new models and characterization techniques to help understand the fundamental and active properties of oxide materials. Work on precursor materials and deposition / growth processes is aimed to achieve full control of the material properties. The structure of materials at the nano-level is then addressed - both by the thin films and nanowires, which are investigated to determine their effects on the material functionality. Demonstration of the engineered electronic (e.g. semiconducting behavior, gas sensitivity) and optoelectronic (light emission, color conversion) functionalities is achieved through integration in proof of concept devices. This requires mastering of the interfaces between oxides with different properties and also between oxides and the substrates such as ceramics, silicon and polymers.
These goals are achieved by addressing the four key topics relevant for electronic oxide material development:
• First principle modelling of oxide materials: Predict the relevant electronic film properties such as electronic structure, doping and defect mechanisms.
• Synthesis of new n- and p-type ASOs, new amorphous TCOs and oxide based p-n junctions.
• Low temperature, damage free deposition and patterning techniques to integrate the new material in device concepts and to certify the functionality for applications foreseen in the field of automotive and sensor applications, flexible electronics and UV-optoelectronics.
• Metrology: ORAMA will advance the characterization techniques formerly used for Si semiconductors towards metal oxides at the nano scale level.
ORAMA is also investigating into novel processing techniques for oxide electronics, such as atomic layer deposition (ALD) and patterned deposition by means of Ink-Jet printing. Further the synthesis of liquid precursors which are required for the printing of p-type thick films will also be done. These precursors are selected from the materials which are used to process thick film structures (thickness range: a few 10 µm range) by printing on different substrates for testing of gas sensing properties.
A new metrological innovation in ORAMA is the Hall effects measurement set-up used to perform better temperature-dependent measurements of the four coefficients (M4C) in ASO and TCO specimens. These measurements combine the current electrical (resistivity) and magneto-transport (Hall) measurements with thermoelectric (Seebeck) and magneto-thermoelectric (Nernst) measurements. To perform such measurements reliably, the ability to measure voltages below the Johnson noise level of the corresponding resistances is required. Therefore, as any DC system will be inadequate, it was committed to employ a single/double modulation (AC) mode operation to restrict measurement bandwidth.
A further objective is to make a flexible AM OLED display, as OLED displays. OLED displays have more stringent requirements when it comes to TFT performance.
The oxide materials developed in ORAMA have a high potential to enable new electronic/IT products by enabling current Si-based functionalities to be implemented on flexible substrates and owing to their intrinsic transparent properties. This will enable the development of flexible and transparent devices. Furthermore, these materials and associated technologies also have two major advantages over conventional electronics: reduced cost and reduced environmental impact.
The potential impact is therefore much greater as a replacement technology for current Si-based systems.
Apart from the novel research activities, ORAMA is also training the fellow researchers: summer schools have already been implemented in the context of the international TCM (Transparent Conducting Materials) symposium 2010 and 2012 held at FORTH in Crete. In May 2014, the 3rd ORAMA summer school had been held in Lille, France, to present the current scientific results to a larger community.
Issues related to safety and sustainability of the new materials and devices will be considered taking the expertise of the automotive industry directly into account. Additionally, an Industry Advisory Boards (IAB) was installed with members of 3 large companies to get feedback on our research for the industrial needs. The overall goal of the IAB is to accompany the project with the knowledge from the industrial side of view. Due to the industrial background they are able to give advices for the industrial feasibility of new products. Furthermore, they will evaluate the devices within an industrial content.
WP 1: Modeling of materials, processes and applications on multiple scales: Within this work package, the fundamental understanding of oxide materials for electronic applications is provided by using a multi scale modeling. Thereby, the experimental synthesis and characterization data being obtained on specific TCO and ASO materials in the other RTD WPs is supported, validated and explained.
WP 2: Synthesis of precursors and target materials: The goal of this work package was to support investigations of different combinations of metal oxide materials to determine which compounds have the potential for best all-around performance, respectively for n- and p-type TCO and ASO applications, as well as for dielectric applications. Therefore, the theoretical modeling results of WP 1 are validated by checking the solid solubility. In addition, the preparation of targets for sputtering and for solution and suspension precursors for film and structure processing in WP 3, WP 5 and WP7 are provided.
WP 3: Development of thin film processes using fab and non fab routes: The goal of this work package is to provide process techniques suitable for electronic grade oxide film deposition by means of fab and non fab techniques. Challenging demands on the control of phase composition and stoichiometry have to be met to achieve desired doping effects and electronic properties foreseen. This holds not only for binary but also for ternary and quaternary compounds. Furthermore, low temperature techniques have to be addressed to take advantage of flexible substrate materials.
WP 4: Characterization and material properties: There are three main objectives of this work package. The first is to provide tools and protocols for a baseline characterization of the most relevant oxide materials properties developed in the other work packages where thin film synthesis is performed (in view of the requirements for lighting and sensors of the automotive industry): The second is to develop novel methods for the in-depth analysis of oxide material science relate electronic phenomena. The third is to apply these methods and to disclose the finding to the oxide material scientific society.
WP 5: Development of tailored metal oxide films: The goal of this work package is to explore novel physical and chemical characteristics of multifunctional tailored amorphous and crystalline passive (TCO) and active (ASO) oxides and amorphous dielectrics, all processed at low temperatures in rigid and flexible substrates, for electronic and optoelectronic applications. To target this objective, the work planned will be fully supported by the modeling activity in WP 1, using the sintering targets and precursors developed in WP 2 and employing the processes implemented in WP3. As output of the work performed, specifications of the materials developed will be supplied aiming for their use in electronic Cooperation Collaborative project (IP) and optoelectronics, able to fully satisfy their requirements, such as for building up electronic discrete and integrate circuits, as CMOS; n- and p-type thin Film Transistors (TFT), fully oxide based; or materials’ integration in novel sensing and LED devices.
WP 6: Proof of concept for oxide materials for optoelectronics use: The goal of the work package is to verify the potential of various new functionality oxide materials for the use in optoelectronic devices: It addresses the understanding and control of optical properties of nano layer stacks containing TCOs and interfaces to semiconductors, dielectrics and metals, the proof of concept of color conversion within TCOs for white light generation and the proof of concept for light emission from metal oxide hetero junctions using stable p- ASO, type-II-emission using III-V / II-VI combination and oxide nanowires/p-ASO combination.
WP 7: Proof of concept for oxides materials for electronics use: The objective of this work package is to demonstrate control of the properties of the materials processed under WP 3 and WP 5, aiming at their use in electronics, at both micro and nano scale. To prove the outstanding electronic performance of the matured TCO and ASOs, simple device concepts will be developed, supported by modeling performed in WP 1, such as p- and n-type full oxide based TFT; CMOS; investigation and characterization of p-type oxides for sensing applications. It was agreed on three demonstrators: DEMO#1 is a touch panel with reconfigurable icons for the steering wheel, DEMO#2 is a multifunctional glazing material and DEMO#3 deals with gas sensor applications in the automotive environment.
WP 8: Exploitation, training and knowledge transfer: The objective of this work package is to maximize the ORAMA impact in terms of contribution to the materials science and commercial applications. The novel oxides are expected to be integrated in several electronics and optoelectronics devices with a wide, huge potential economic impact (low costs production, reduction of energy consumption, etc.) and societal impact (increase comfort and consumer safety, pollution reduction, etc.). The specific objectives of this work package are: (i) to exploit all scientific results of the project towards automotive sectors and other emerging high impact fields as flexible electronics; this will be achieved by means of proper management of IPR; (ii) to properly manage the knowledge transfer inside/outside the consortium by means of traditional and innovative tools to exchange knowledge between specialists and to facilitate the implementation of the developed materials and technologies into industrial environments; (iii) to inform the scientific community and society about the results of ORAMA by promoting and participating to initiatives with the goal of improving exchanges between science and society; (iv) to exchange knowledge between scientists and to elaborate a training program (summer schools, courses, seminars) for formation of specialists in materials science and integration in final devices.
WP 9: Management: The objectives of the management work package are also detailed in section 2, namely: (i) To achieve the technological aims of the project and promote the use of ORAMA results in other scientific disciplines and market sectors, (ii) to ensure that all ORAMA partners achieve the objectives which their organizations set out for participating, (iii) to use European R&D resources efficiently and effectively, including maximizing links to relevant national, European and worldwide initiatives and (iv) to broaden the expertise of all participants working within the project in both technology and exploitation.
WP 10: Scientific management: The objective of this work package is to maximize the effectiveness of the ORAMA work program delivery by developing detailed scientific and technical plans – Action Plans - for each task on an annual basis. This enables interactions between tasks to be identified and coordinated and will enable the project roadmap to be updated to take account of actual progress at the start of each year.
Work Package 1: Modelling of materials, processes and applications on multiple scales (CEMOP/CENIMAT, FHG-IWM, FHG-IST, UNICAM)
The work package 1 of the ORAMA project was focusing on various aspects of modelling on multiple scales concerning microscopic structures, growth processes and devices characteristics.
The key semiconductor device in large-area electronics is the thin-film transistor (TFT). In this device, two electrodes – source and drain – are connected to each other via a thin semiconductor layer (typically few tens of nanometers thick), whose electrical conductivity is controlled by the third electrode – gate. By varying the voltage applied to the gate, a desired amount of current can flow between the source and the drain. Being able to accurately predict and simulate, prior to fabrication, the electrical behavior of TFTs, and hence that of designed electronic devices, is of crucial importance, because this can reduce drastically time and cost effort to find “the best option”. One of the important achievements from the modelling part of the project ORAMA is the construction of so-called compact models, specially developed to describe, in a computationally efficient way, the behavior of TFTs made with amorphous oxide semiconductor (AOS) materials.
To do so, it was important to understand the underlying mechanisms of the carrier transport (i.e. how electric currents flow) in those materials. Different materials provide a variety of mechanisms, and each mechanism appears in a particular manner when we try to describe mathematically the relationship between the electric current and applied voltage. In active oxide semiconductor (AOS) materials, the primary two mechanisms are: trap-limited conduction and percolation, which prevail under low and high gate voltage, respectively. The electrons “become current” when they are in the conduction band, a pathway that only electrons with sufficiently high energy can reach. The trap-limited conduction is associated with the localized states which can trap those electrons and is governed by multiple trapping and release events. This mechanism had already been extensively investigated and modelled in the case of amorphous silicon, which is the first widely used (and still dominant) semiconductor material in TFT electronics. Now, the percolation originating from the presence of barriers in the conduction band was new in the compact modelling scenario. Within ORAMA we have developed a series of physics-based expressions describing the effect of this mechanism on the electrical behavior of TFTs, and we created compact models which duly translate the co-existence of two mechanisms. These models have been published in scientific journals and conferences, and implemented in circuit simulation software, showing a good agreement with experimental TFT characteristics as well as the operation of test circuits.
In order to improve the microscopic understanding the oxide-semiconductor materials which are used nowadays in the fabrication of TFTs and other electronic devices, another part of this work package focused on the modelling of semiconducting oxides at the atomic level using a combination of classical atomistic and quantum-mechanical electronic-structure simulation methods. The methods employed were state-of-the-art and included molecular dynamics, reverse Monte Carlo, and density functional theory with pseudopotentials and a variety of exchange-correlation functionals. The aim was to provide fundamental understanding of the microscopic behavior of a range of relevant ternary and quaternary oxides, mainly derived from ZnO, and to guide their experimental fabrication and integration into devices. Focus of interest included a comparison of crystalline and amorphous structures, the characteristics of atomic defects and dopants, and the properties of interfaces with other oxides and nitrides. The work addressed both AOSs and transparent conductive oxides (TCOs). The efforts were strongly linked to several other experimental work packages. Some key studies succeeded in (1) predicting the effect of trivalent dopants (In, Ga and Al) on local coordination and electronic structure in single-crystalline, multi-crystalline and amorphous ZnO; (2) understanding the defect properties of crystalline ZnO:Rh and ZnO:Ir and the effect on p-type conductivity; (3) analyzing the effect of defects and disorder on the electronic properties of ZnIr2O4; (4) predicting the presence of sub-gap states in Zn and Sn-based oxides using various exchange-correlation functions; (5) analyzing the electronic properties of stoichiometric and non-stoichiometric grain boundaries in ZnO.
A third topic of the modelling in the ORAMA project was on establishing a Particle-in-Cell Monte-Carlo (PIC-MC) plasma simulation model for the magnetron discharge behaviour. In a first step, the plasma chemical model for sputter processes in Ar/O2 gas mixtures was extended in order to obtain the growth conditions at the substrate in detail. Subsequently, 2D plasma simulations were carried out. The 2D PIC-MC simulations revealed that the main mechanism for plasma damage are highly energetic oxygen ions originating from the sputtering process at the ceramic target and accelerated in the plasma sheath. There is a good correlation between the experiments and the 2D PIC-MC simulations. Furthermore, in cooperation with OSRAM Opto-Semiconductor, it was achieved to describe the plasma damage within a computer model of a specific PVD sputter coater for LED metallization. 3D PIC-MC simulations reveal that propagating plasma fluctuations are an important mechanism in DC and RF-superimposed DC magnetron discharges. Under certain conditions, these plasma fluctuations can cause significantly enhance the plasma potential leading to an acceleration of positive ions. For the specific sputter coater setup at OSRAM OS this was identified as being an important mechanism for enhanced plasma damage during coating of the LED devices.
While PIC-MC simulations can be used to predict particle fluxes at the substrate, they do not provide information about the detailed film growth mechanisms. In order to learn more about film growth mechanisms while staying in the frame of reactor-scale modelling, a heuristic reactive wall reaction model extension was developed. This model extension allows to define a set of possible wall material phases and to define a detailed chemical reaction scheme between gas and wall species, which can be temperature and energy dependent. After completion of the model extension, the reactive sputtering process of doped ZnO:Al TCO layers was chosen to demonstrate the potential of the new model feature. A property of particular interest in ZnO:Al layers is the Al concentration profile and its doping efficiency. Al atoms can be incorporated into the layer as substitutes of Zn atoms in the ZnO crystal structure, in this case it acts as donor which is the base for the n-type conductivity of ZnO:Al layers. Another possibility is that Al form insulating Al2O3 precipitates, which obviously do not contribute to the electric conductivity. It was shown that these two incorporation mechanisms can be described within the frame of the heuristic reactive wall reaction model, and reasonable correlation with experimental data was achieved.
Altogether the work package 1 of the ORAMA project successfully achieved computational modeling and simulation tasks focusing on relationships between structure and composition, property and processing of TCO and AOS materials in TFT devices across multiple size scales.
Work Package 2: Synthesis of precursors and target materials (CEMOP/CENIMAT, FHG-IST, FHG-ISC, JSI, TNO, Soleras)
The objective of WP2 was to carry out investigations of different combinations of metal oxide materials to determine which compounds have the potential for best performance, respectively for n- and p-type TCO and ASO applications, as well as for dielectric applications; and to validate the theoretical modelling results, obtained in WP1. To reach this goal, ceramic targets for physical vapour deposition, both on laboratory scale (‘research-grade’, dia ~50 mm) and on industrial scale (planar dia 6-inch (~ 150 mm) and rotatable, length up to ~3500 mm) were prepared, solution and suspension precursors for thin films or patterned structures, and multicomponent metal-oxide powders and pastes for screen-printing of thick films for gas-sensor testing, respectively, were processed. Clearly, the research within WP2 was strongly related to WPs 3, 4, 5 and 7.
Multicomponent indium-free oxide targets for sputtering deposition of amorphous n-type oxide films with a high chemical and phase homogeneity and uniform microstructure were processed by mechanochemical activation of the reagent-oxide powder mixtures. The process resulted in a reduction of crystallite sizes of constituent powders as confirmed by XRD and contributed to enhanced sinterability of the powders. The investigated n-type In-free formulations were based on selected compositions, such as ZnO - SnO2 (ZTO, Zn : Sn = 2 : 1, 1 : 1, 1 : 2 atomic ratio), SnO2 - ZnO - Ga2O3 (GZTO, Zn : Sn : Ga = 60 : 33 : 7 atomic ratio), ZnO - Ga2O3 (GZO, Zn : Ga = 45 : 2 atomic ratio) and ZnO - SiO2 (ZSO, Zn : Si : Ga = 96 : 4 atomic ratio). The ceramic targets were sintered at optimium conditions (temperature, time, atmosphere, e.g. the GZTO target was sintered at 1350 oC for 10 h in O2 atmosphere) to yield dense ceramic materials with equilibrium phase composition and uniform microstructure, and delivered to project partners within WP3 and WP5. The optimum compositions of both binary and ternary oxide mixtures were also proposed based on co-sputtering experiments.
A further focus was on development of ceramic processing of targets for p-type oxide films. The solid-state synthesis of the delafossite CuAlO2 ceramic powder was optimized to yield a single-phase material. It was found that use of the nano-sized Al-precursor, boehmite, and heating in inert atmosphere were crucial for obtaining the pure delafossite phase. Sintering conditions for obtaining dense ceramics were established: 1100 oC for 2 h in air atmosphere. Dense, single-phase delafossite ceramic targets were processed and delivered to project partners for sputtering experiments.
Both n- and p-type metal oxide particles were synthesized with the aim to explore which materials in the form of thick films have the potential for best sensor performances. The n-type oxides included ZTO and GZTO, and the p-type materials included Co3O4, Au-and Pd-doped Co3O4, CuO and CuAlO2. The p-type oxides were prepared by solution-combustion synthesis. The nano-crystalline oxide powders were further used for screen printing of thick-films on platinized alumina substrates to realize the gas sensors within WP7.
In the frame of research of precursors for chemical route applications the focus was on the design and synthesis of solutions for thin film deposition by spin-coating or dip-coating and of precursors (inks) for patterning of 2D-structures by inkjet printing (for details refer to WP3). The materials compositions included n-type oxides (ZTO, both undoped and Al-doped, and GZTO), p-type oxides (delafossite CuCrO2) and high-K dielectrics (Ta2O5 and Ta2O5-Al2O3-SiO2, TAS, Ta : Al : Si = 8:1:1 atomic ratio). The formulations of individual precursors were designed for a specific processing route, depending on the properties which are important for either deposition of the films or printing on glass substrates.
Different solutions chemistries were addressed, including alkoxide based sol-gel, combustion synthesis, amine, or chloride routes. Hydro/ lyothermal processing routes for amorphous ZTO solutions were developed. A chloride-based synthesis yielded amorphous ZTO nanoparticles that could be applied for the deposition of thin films. Plane films were prepared by both dip- and spin-coating experiments, the porosity and electric conduc¬tivity of amorphous ZTO films were optimized by multiple coating/firing cycles. Both Ta2O5 and TAS coating-solution formulation and the heating profile were optimised to reduce trace organic impurities and leakage of respective thin films. Dense amorphous high-K dielectric thin films on patterned glass substrates processed at temperatures 300 – 350 oC were integrated into thin film transistors (TFTs), for details see WP5 and WP7.
It was possible to adapt properties (viscositiy, surface tension, contact angle with a selected substrate and volatility) of Nd-doped TiO2, CuCrO2, ZTO, Ta2O5 and TAS precursor solutions to the specifications required for ink-jet printing. Further refinement of solution properties and ink-jet parameters allowed the deposition of microstructured films. Mainly due to restrictions regarding lateral resolutions pad-printing experiments were not further pursued.
Supporting the development of oxide electronic technology for the European market, the objective was not only to prepare the new target and precursor materials for fabricating novel indium-free functional films, but further the development of viable process technologies for bringing those materials to the industrial scale of rotatable magnetron targets and demonstrate their sustainability in the market. While planar targets traditionally play a strong role in the display industry, there is an increasing demand for rotatable targets in large area and display applications, in particular for the oxide electronic market. Some advantages of rotating versus planar targets are:
• More material is available for deposition, minimizing coater downtime
• Increased process stability through continuous cleaning of the targets by the plasma
• Higher maximum power density on the target and higher deposition speed through optimal distribution of the thermal stress.
In the project, high-performance target fabrication by mechanical-chemical activation and sintering was extended to hot-pressing and thermal-spraying, allowing the manufacture of single-piece ceramic rotary targets up to 3,5 meters long for uniform large-area film deposition on wafers, glass and roll-to-roll processing.
With focus on amorphous n-type active semiconducting oxides, full-size rotary targets for the Zn-Sn-O and Zn-Sn-Ga-O material systems were developed. These targets are principally composed of Zn2SnO4 spinel with 99,8% purity and densities above 85%. Sputter powers can exceed 18 kW/m dc, leading to exceptionally high throughput with deposition rates above 70nm m/min. Production runs have shown that the targets are highly stable at the working point and lead to fully transparent coatings even in “metallic mode” sputtering, avoiding oxidation of adjacent metallic functional layers in the same device. After tailoring the growth conditions and mediating film damage through careful coater design, we could demonstrate that these sprayed targets lead to high performance thin-film transistors with mobility μFE larger than 12cm2/Vsec, Von~0V, S~ 0,18 V/dec and Von/off>1010, approaching the performance of the indium-containing TFT’s and, indeed, benchmarking indium-free oxide TFT’s. It is remarkable that these high performance transistors can be obtained from both sintered and thermal sprayed targets, being a testimony to the robustness of this material system. In addition to oxide electronics, other global markets in large area glass and even thin-film photovoltaic are expected to benefit from this new product development. Under a pending patent application (Patent application PCT-14020SL00WO 2013), the ZTO targets are now introduced into the market and commercially available up to 152” length and 6 mm thickness on 133 mm diameter. Within this program, we could successfully demonstrate the sustainability of these new electronic oxide materials targets, leading to renewed growth opportunities within Europe.
Work Package 3: Development of thin film processes using fab and non fab routes (CEMOP/CENIMAT, FhG-ISC, FhG-IST, FORTH, JSI, OSRAM, TNO, UNIBS, UNICAM, Uni-Giessen)
The objectives of WP3 are the development of process techniques suitable for electronic grade oxide film deposition by means of fab and non fab techniques. This means processes which allow for ideal growth conditions in terms of balancing particle fluxes, taking low energetic activation of growth process into account and allow for in-situ growth control to adjust phase composition and stoichiometry. In principle, process techniques for oxide materials addressing four growth morphologies for different materials and applications were investigated: (i) fully amorphous phase material; (ii) columnar grown polycrystalline material, (iii) single crystalline films grown on crystalline substrate, and (iv) large grain size polycrystalline material where grain size exceeds 10 µm by annealing of amorphous films. Furthermore also patterned deposition to circumvent the complexity and costs of lithography were established. Additional the concept of oxide nanowires with reproducible nucleation and growth of nanorods has been studied.
Soft growth deposition (FhG-IST, FORTH, OSRAM, UNICAM)
With respect to LED it was observed that sputtering processes lead to a damage of the device. Even low energy RF superimposed DC sputtering cause damage of the LED hetero structure by applying a TCO on the GaN. This could be understood even by simulation of these processes. To overcome this problem the main focus after the middle of the project was on ALD because these methods can create TCOs without plasma damage. Mainly ZnO based thin films with different dopants for the LED with ALD were developed. So, Nb2O5, SnO2, TiO2 along with Al2O3 were chosen for the doping the ZnO. The resistivity of the films were in the order of ZnO:Ti < ZnO:Nb < ZnO:Al < ZnO:Sn < ZnO (undoped). The best conductivity and mobility for example from ZnO:Ti was 9.3 x10 4 Ωcm and 20.5 cm2/Vs and for ZnO:Nb it was 1.4 x10 3 Ωcm and 28.3 cm2/Vs. The coatings were used on deposited on p-GaN wafers from OSRAM for further evaluation. With AP-CVD for ZnO:Ti system a promising result has been reached. The resistivity of the materials reaches values up to 6.5*10-4 cm with mobilities of 32.3 cm²/Vs.
Development of techniques for control of phase composition and stoichiometry (CEMOP/CINEMAT, FhG-IST, UNICAM)
The precise control of stoichiometry and phase composition is the prerequisite for the successful multicomponent oxide layer for the subsequent work on dielectric, ASO and TCO development. Diverse PVD techniques and process control from different working partner has been successfully implemented. For the control of deposition process and film properties different methods are developed and used. For example -probe closed loop control of oxygen partial pressure, plasma impedance and self-bias (dc and rf), optical emission spectroscopy of plasma emission and optical transmittance/reflectance spectroscopy was used to control the growing film.
Multi-component oxide film deposition techniques capable for amorphous ASOs
(CEMOP/CENIMAT, FhG-IST, FhG-ISC, FORTH, JSI, TNO, UNICAM)
The evaluation of competing process techniques which have high potential for the precisely controlled tailored growth of electronic oxide materials have been investigate into a-ASO films using Zn-Sn-O and Zn-Ga-Sn-O as model systems to benchmark the relevant processes. In WP2 target materials for planar and rotatable setups has been developed and sputtered with different techniques. High carrier mobility up to 50 cm2/Vs with GFS process has been reached. Nevertheless for the final demonstrator standard sputtering techniques have been used. The PVD processes also seem to have an advance in preparing semiconducting material, as the CVD processes often produce films with un-detectable electronic properties and carrier mobilities with 4.5 cm2/Vs maximum for Sol-Gel-deposition has been reached by now. For industrial relevant application the rotatable targets reaches mobility values up to 10 to 20 cm²/Vs at higher carrier concentrations of 1017 1019 /cm³. In test devises with lower carrier concentration field-effect-mobility of 3 cm²/Vs has been reached. With all considered techniques, the optical properties are all very good with T550nm > 80 %, regardless which deposition process was used.
Wet chemical processes (FhG-ISC, CEMOP/CENIMAT, JSI, TNO)
The wet chemical synthesis by means of Sol-Gel deposition and low temperature wet chemical synthesis allows not only for a very flexible, precisely adoptable process route to deposit multicomponent oxides such as p-ASO but also for patterned deposition by means of pad and ink jet printing. During the project regarding the pros and cons the inkjet printing was mainly used. The properties of Nd-doped TiO2, CuCrO2, ZTO and Ta2O5 precursor solutions have been successfully adapted to the specifications required for ink-jet printing. Moreover, the Zn:Sn ratio has been also adjusted over a wide range of compositions.
Oxide nano wire manufacturing techniques (UNIBS, Uni-Giessen)
Oxide nanowires open up promising pathways to electronic functional oxides since high mobility reported for single crystal nanowires ensures better transport properties than those of thin films. Moreover low point defects or extended defects density is observable in nanowires giving way to superior optical properties. Two promising pathways were evaluated: MBE growth of oxide nanorods (Uni-Giessen) and Preparation of NWs by evaporation-condensation process (UNIBS), with VLS (vapor liquid solid) and VS (vapor solid) growth mechanisms. The p- and n-type oxide nanowires have been successfully grown on different substrates such as alumina, sapphire and even flexible kapton. As an example UNIBS successfully synthesized p-type CuO NWs on flexible kapton substrates via a simple thermal oxidation technique. Furthermore n type ZnO nanowires on p-GaN were successfully grown.
Post deposition treatment techniques (FhG-IST, FhG-ISC, FORTH, TNO)
Modification of oxide by means of post deposition treatment is a feasible technique to modify microstructure and doping and thus, the electronic and optical properties of the layers. In this Task especially plasma annealing processes and thermal annealing were used. The outstanding properties after thermal annealing has been showed by TiO2:Nb which resulted large grain size of n-type TCO exceeding 10 µm. Even with a temperatures annealing of 350 °C a resistivity of 1.2*10-³ cm has been reached.
Non-fab deposition techniques (CEMOP/CENIMAT, FhG-ISC, FhG-IST, JSI)
The objective of this task was the development of wet chemical and PECVD processes for the fine patterned deposition of oxide films for electronic oxide materials to circumvent the difficulties and costs of conventional lithography for fine patterning. The most promising technique for additive patterning has been showed by the ink-jet printing on the realization of printed TFT.
Work Package 4: Characterisation and material properties (CEMOP/CENIMAT, EKUT, FhG-ISC, FhG-IST, FORTH, OSRAM, UNIBS, UNICAM, Uni-Giessen,)
Today professional and customer electronics rely on Si, SiGe and III-V semiconductors, on which, further development, started to face technological and economic constraints due to their need for high temperature processing, unsuitability for large area or flexible devices, optical opacity and scarce materials (i.e. In). The emerging class of oxide semiconductors (Active Semiconductor Oxides –ASOs- and passive Transparent Conductive Oxides –TCOs- both of n-type and p-type) is able to overcome many of these limitations, enabling modern industry to realize new devices like UV LEDs for high quality / high efficiency white lighting and active matrix transparent / see-through displays, achieving at the same time practical advantages of, e.g. lower fabrication costs and more sustainable use of natural resources (indium free). The development of new oxidic materials (ASOs & TCOs) for industrialization requires, besides the established investigation means, novel research strategies, techniques and instruments as well as to define new evaluation parameters in order to ensure the expected material quality without overseeing the necessity to prove the functionality of these compounds in device applications. Continuous scientific efforts based on nonconventional explorative approaches are needed in field of transparent semiconductors to eventually enable the European manufactures to stay competitive at global scale.
A key task for the partners in the ORAMA project, and, in the same, time the goal of the WP4, has been a thorough understanding of the fundamental properties (structural, electro-optical and chemical) presented by the advanced oxide materials developed within the consortium by using both, state of the art and original characterization techniques. The standard techniques such as: X-Ray Diffraction (XRD), RAMAN, Focused Ion Beam/ Scanning Electron Microscopy (FIB/SEM), Transmission Electron Microscopy (TEM), High Resolution TEM (HRTEM), Cross-section TEM (XTEM), Electron Diffraction (EDX), Atomic Force Microscopy (AFM), Angular Resolved Scattering (ARS), X-ray Photoelectron Spectroscopy (XPS), Electron Spectroscopy for Chemical Analysis (ESCA), Ultra-Violet photoemission spectroscopy (UPS), Rutherford Back Scattering (RBS), Secondary Ion Mass Spectroscopy (SIMS), reflectance, transmittance (UV-Visible-NIR-Mid-IR), Spectroscopic Ellipsometric (SE), X-Ray Reflectometry (XRR), Photoluminescence (PL), Electroluminescence (EL), and Kelvin Probe (KP) provided the tools and protocols for the baseline characterization of the materials. Beyond these, the design, development and application of the novel “Method of 4-Coefficients” (M4C), which accurately measures the electro-thermo-magneto-transport properties of the oxidic semiconductors, providing an in-depth analysis of the advanced ASOs & TCOs, appears as one of the highlights not only for the WP4 but also for the entire ORAMA project. Fulfilling its major goal, WP4, evaluated the behaviour of oxide materials and devices consisting of these oxides under normal and harsh conditions in order to ascertain their reliability and work life time.
Through investigations addressed above, WP4 was able to: (i) provide feedback required to refine the work performed in modelling (WP1), (ii) develop tailored oxide films (WP5) and nanowires (WP3) and (iii) provide the tools and procedures for the certification of oxide materials in their applications for optoelectronics and electronics (WP6 & WP7). In the same time, by evaluating the performance of the advanced oxides, their figure of merit (ratio of the electrical conductivity ‘σ’, to the visible absorption coefficient ‘α’) has been assesed and used as main criterion to select the best ASOs & TCOs developed within ORAMA (WP5) for the partners (FhG-IST, FORTH, UCAM, TNO, UNINOVA, EKUT) having in charge the manufacture of oxide-based electronic and optoelectronic devices. The realized sensors and Thin Film Transistors (TFTs) based on these oxides were evaluated for their long term operation and stability under harsh and accelerated aging tests. The loss mechanisms degrading the device performance have been evaluated (EKUT), identified and, in some cases, better described based on theoretical models proposed by partners (UCAM). New p-type oxides have been developed as bulk and nanowires and tested for their application as materials for improved / nonconventional optoelectronic devices by partners OSRAM and UNIBS.
Nearby, the major advancement within WP4 was the design and development of the M4C technique for the electronic characterization of the “difficult” oxides developed within ORAMA. The method was aimed to accurately investigate the carrier transport phenomena and to extract the associated charge carrier kinetic parameters: concentration, “true” mobility, effective mass and the scattering factor from the values of the resistivity, Hall, Seebeck and Nernst coefficients measured on TCOs and ASOs thin films. Because of the high resistivity often encountered for oxides and to the small voltage signals associated to it, below the intrinsic Johnson (thermal) noise level, a direct application of the method is not possible. Thus, a modulation set-up for M4C measurements was designed and implemented by partner FORTH where by applying a modulated excitation and employing synchronous detection, the measurement bandwidth could be significantly reduced, permitting, in this way, the extraction of the utile voltage signals from below the noise threshold. The implemented set-up has the ability to achieving the three relevant modulations modes afferent to this method: (a) Current modulation, (b) Magnetic field modulation and (c) Thermal gradient modulation. The set-up has been constructed to simultaneously perform double modulation experiments (e.g. perform Hall coefficient measurement applying both current and magnetic field modulations at different frequencies at the same time) to further reduce the interfering noise contributions and artifacts. The sample pattern shape has been designed to conform to the dimensional restrictions associated with minimization of systematic errors and maximization of voltage signals, since unlike measurement configurations (Hall, Seebeck, Nernst) largely differ. The dimensions were chosen in such a way that an enhancement of the measured Nernst voltages can be attained, with, as little as possible, compromise on Hall measurements’ geometry. A sample holder provided with spring loaded contact pins, which allows for the self alignment and easy mounting of the specimens in the set-up cryostat, has been devised. It enables the temperature readout without attaching thermocouples on the device under test. In the design of the holder, important considerations regarding the modulated M4C measurements method, were taken into account: (i) Low thermal mass of the temperature modulated part to permit increased thermal modulation frequency and lower phase errors, (ii) High temperature uniformity in the longitudinal directions of the “hot” and “cold” fingers, to minimize thermoelectric artifacts associated to the Nernst measurements and (iii) Small size differential pair of thermocouples positioned as close to the specimen front surface as possible, to minimize the thermal gradient reference measurements errors. In this way, oxides with resistance as high as 100 MΩ could be measured and it was the use of M4C which revealed that spinel structures developed within ORAMA were p-type materials.
In conclusion, it has to be noticed that the ORAMA partners have adopted the appropriate characterization techniques to successfully investigate the diverse properties of the selected metal oxide structures and to evaluate the performance of the materials as well as their functional limitations in device applications. During the project a new and valuable experimental method (M4C), which expanded the consortium facilities, has been established in the frame of WP4.
Work Package 5: Development of tailored metal oxide films (CEMOP/CENIMAT, FhG-IST, FhG-ISC, FORTH, JSI, OSRAM, TNO, UNIBS, UNICAM)
Transparent electronics is today one of the most advanced topics for a wide range of device applications. The key components are wide bandgap semiconductors, where oxides of different origins play an important role, not only as passive component but also as active component, similar to what is observed in conventional semiconductors like silicon. Transparent electronics has gained
special attention during the last few years and is today established as one of the most promising technologies for leading the next generation of flat panel display due to its excellent electronic performance.
This WP aimed to establish a portfolio of metal oxide materials that can be deposited by a variety of growth techniques and employed together to deliver the broad range of devices that are required, including conductors, semiconductors and dielectrics to be integrated in new devices like LEDs transparent circuits and active matrices / see-through displays (materials for gas sensors were developed in WP2, 3 and 7), achieving at the same time practical advantages of, e.g. lower fabrication costs and more sustainable use of natural resources (indium free). Thus, this WP assisted the initial development of materials and structures, supplying the required inputs to the work to be performed in WPs 6 and 7, which will see the development of systems employing these materials. Three distinct classes of metal oxide materials were developed: transparent conducting oxides (TCOs); oxide semiconductors (OSs); and high-k dielectrics. A key advantage of the metal oxide materials is the prospect of being able to produce them at very low temperatures onto plastic (flexible) substrates as well as rigid substrates.
The work performed in this WP concerning the conductive and semiconductor oxides has been focused on sputtering, CVD and ALD deposition since the developments made on solution based deposition and non-fab techniques were addressed in WP2
Amorphous and polycrystalline conductive oxides
This task covered the development of conductor n-type and p-type (amorphous and polycrystalline) oxide thin films using the deposition techniques specified in WP3, namely sputtering techniques (RF, DC, HiTUS and GFS) but also ALD and APCVD.
UNINOVA, FORTH and FhG-IST have been involved in the development of sputtered indium-free n-type multicomponent binary or ternary ZnO or TiOx based oxides, involving element combinations such as Si, Sn, Ga, Al, Zr, Nb, identified in the simulation activity of WP1. It was identified that ZnO based materials were most suitable ones to get the desired optical and electrical properties. From the dopants that have been tried, a resistivity in the range of 10-4 Ω.cm was achieved via RF sputtering doping ZnO with Si, Al or Ga. It was also verified that high carrier mobility TCOs (≈ 47.1 cm2/V.s) can be obtained by depositing of intrinsic ZnO in an atmosphere of Ar+H2 with (1.5% of H2), with an average transmittance in the visible (AVT) close to 85% (glass substrate + ZnO film).
Furthermore, FhG-IST has received two rotatable target from Bekaert/Soleras, made of ZnO:Sn material with Zinc:Tin ratio = 68:32. These rotatables have been sputtered with a DC and MF process.
Titanium and Tin Oxide (SnO) were the dopants chosen by TNO to develop TCOs based on ZnO deposited by APCVD. The Ti revealed to be better choice when compared to SnO; all the films present transmittance close to 80% in the visible range nevertheless the lowest resistivity for ZnO doped with Ti is in the order of 1x10-3 Ω.cm.
FhG-IST has developed doped TiO2 with Nb with anatase crystalline phase. These films present improved electrical characteristics (resistivity of 1.37x10-3 Ω.cm) compared to the intrinsic one studied at UNINOVA. The dopant incorporation affects the optical properties as well, where the AVT decreases from 80% (pure TiO2) to 63% (TiO2:Nb).
The development of p-type TCOs was done making use of NiO, ZnO:N, CuAlO2 and ZnO:Ir(OH)x. NiO thin films were develop at UNIBS and FORTH. Both partners deposited NiO by RF sputtering. The best results were obtained when depositing in plasma containing 2.8% O2 and the films showed the highest transmittance (~40%) in the visible region of the spectrum, p-type conduction and a resistivity between 10-1-101 Ω.cm.
CuAlO2 delafossite was studied at FhG-IST and UNIBS using reactive rf magnetron deposition. FhG-IST has made the depositions by co-sputtering from metallic Cu and Al targets while UNIBS has used a single metallic Cu-Al(1:1)-target in transition mode and from a oxide target -CuAlO2 (sintering by JSI). Films deposited at room temperature and annealed at 600°C (Ar) presented a resistivity of 3.20x10-1 Ω.cm and AVT near to 50%.
ZnO:N films with post-deposition plasma treatment in NH3 plasma have shown p-type conduction but the electrical resistivity was two high (3.20101 cm) to be considered as TCOs. ZnO:IrOx were deposited at FhG-IST by HIPIMS and RFMS. The Hall effect measurements revealed films with resistivity in the range of 10-2 Ω.cm The Seebeck coefficient was measured and the p-type conduction was confirmed. All the films are amorphous, with a bandgap in the range of 2 to 2.5 eV with low transmittance.
The main requirements for n-type TCOs were a transmittance around 90% and resistivity close to 1-210-4 cm. while for p-type ones the main goal was to get a resistivity close to 10-2 cm with reasonable transmittance. Concerning n-type TCOs the doped zinc oxide (ZnO) while for p-type ones copper-aluminum dellafossite (CuAlO2) presented the best balance between transmittance and resistivity, that best suits the initial goals. However one cannot be strictly focused on this figure of merit to select the most suitable TCO since it does not take into account the mobility or the processing temperature that are also very important and defined as selection criteria in the DoW. Finally it must also highlighted that despite not satisfying the criteria written in the DoW, the ALD and AP-CVD TCOs being developed at TNO present very interesting electro-optical characteristics. Despite the high processing temperature used, they were integrated in LEDs developed in WP6 due to the absence of substrate damage during deposition. This way they were also be considered as selected materials.
Amorphous and polycrystalline oxide semiconductors
This task seeks the development of highly uniform, homogeneous, indium-free multicomponent oxide semiconductors that will be able to act as an alternative in different electronic and optoelectronic applications, such as in TFTs , sensors and LED fabrication, feeding WP6 and WP7. Different materials were developed (Zinc-Tin-Oxide, TiOx based oxides for n-type and ZnO:IrOx and several deposition techniques were used, including PVD (sputtering), CVD (Atmospheric pressure), ALD, PECVD and sol-gel routes. The films produced by sol-gel route are described in detail in WP2 reports and will not be mentioned here.
The development of n-type oxide semiconductors was focused on Zinc-Tin-Oxide materials. Several partners were involved in this task such as UNINOVA, FhG-IST, FORTH, UNICAM and TNO (also JSI in sol-gel routes). ZTO films developed at UNINOVA were not possible to characterize by Hall-Effect due to the low carrier concentration. Still, I-V characteristics allowed to extract ρ=5x102 Ω.cm after annealing at 200 °C, decreasing to 0.78 Ω.cm after a 300 °C annealing. In terms of TFT operation, this allowed for field-effect mobilities (μFE) of 4.8 and 13.7 cm2/Vs after 200 and 300 °C annealing, respectively, as could be seen in detail in WP7s. Later in the project the deposition condition were optimized for maximum processing temperatures around 150ºC and these layer were successfully integrated in TFT and matrices processed in plastic substrates.
UNICAM has used HiTUS sputtering and FhG-IST hollow cathode sputtering to deposit SnO2 and Zn-Sn-O producing amorphous ZTO with tuneable resistivity between 10-1 to 108 Ω.cm and Hall mobility up to 45cm2/V-s.. These films were tested in TFTs but were not selected to be integrated in the final demonstrators due to the processing temperature used.
FORTH has worked on Nd-doped TiO2 deposited from TiO2:Nb target (at.% O:Ti:Nb=72:16:12) by DC magnetron sputtering in %O2-Ar plasma. The films had been highly resistive but post-deposition annealing did not affect their properties regardless the annealing time (up to 20 min), temperature (up to 550oC) and ambient (Ar, N2 or forming gas). This behaviour was attributed to the high percentage of Nb in the target and subsequently in the resulted TiO2 films inhibiting any changes to take place. These films were not used in WP6 and WP7.
Finally, one must say that Soleras was also involved in this task. They have produced large area rotable targets that were used to deposit ZTO and GZTO in their own labs and also at FhG-IST. These layers were used on TFTs and the results obtained were satisfactory, validating the upscaling of the composition defined at lab scale.
Concerning the p-type oxide semiconductors FhG-IST and UNINOVA were involved in developments of ZnO:IrOx and SnO/SnO:CuO multicomponent oxides, respectively. ZnO:IrOx films were tested in TFTs but with no p-type modulation. On other hand TFTs based on SnO (polycrystalline) and SnO:CuO (amorphous) allowed for p-tpy devices with filed effect mobility reaching 4 cm2/V-s. These films were successfully used in WP7 to produced CMOS like devices.
On other hand UNIBS p-SOs, copper and nickel oxide (CuO and NiO) also using RF magnetron sputtering in an argon/oxygen mixed environment. Reference values for annealed samples at 400 ºC are in the range of 10-1 Ωcm. These films were developed for gas sensor applications and fabrication of heterojunction with ZnO nanowires for light emitting devices. Finally, CuAlO2 delafossites were also developed both by FhG-IST and UNICAM. For the phase composition on the crystal structure, all samples have been investigated by means of XRD. The possible composition from Cu, Al and O-atoms are CuO, Cu2O, Al2O3, CuAl2O4, and CuAlO2. It could be found that with increasing annealing temperature, the ratio of delafossite material could be increased up to 100% at 1000 °C.. The films were p-type but the sheet resistance was in the range of some tenths of megaohms. When using target prepared by partner JSI for the deposition of CuAlO2 for gas sensing measurements it was observed by XRD the presence of a peak associated to monoclinic CuO, suggesting that a phase changing occurred during ageing even when an ageing procedure at 500°C in ambient air was done to stabilize thin film for gas sensing.
High-k dielectrics and low defect density interfaces
This task aimed the development of nanolaminated dielectrics and multicomponent oxides based on binary and ternary compounds processed at low substrate temperatures, either in rigid or flexible substrates, by the routes defined in WP 3. These films should be compatible with the surrounding electronic active layers (ASOs), to be used in optoelectronics (WP6) and electronics (WP7) applications.
The work at UNINOVA has been focused on multicomponent dielectrics deposited by sputtering. Multicomponet dielectrics based on mixtures of high-k/low-Eg with low-k/high-Eg have been developed by RFMS without any intentional substrate heating. Most promising results were obtained on the mixtures of Ta2O5/SiO2 and HfO2/SiO2 that have reached the goal concerning the leakage current (below 10-8 Acm-2). The insulation properties of these dielectrics as well as the interfacial properties with oxide semiconductors were further improved when using nanolaminates where these dielectrics were sandwiched between SiO2 thin layers. The breakdown voltage of such layers is above 5 MV cm-1. Just a note for the dielectric constant value on these films (between 10 and 14) will depend, of course, on the thickness and total number of SiO2 layers as this will reduce the total capacitance.
UNICAM is also involved in task 5.4 and has developed specific work on the study of deposition of amorphous HfO2 layers with low interface damage using HiUS. HiTUS process allows Hf subplantation leading to film densification and cubic liken amorphous phase hafnium oxide (ca-HfOx) phase. This deposition technique allows for deposition of high k for superior TFT and MOS device performance, at low temperature and high deposition rate. J-E characterisitics in MIS structures shown the breakdowns at 3.5 MVcm-1 and Schottky Emission, with Field-induced lowering of barrier b between EF,metal & CBinsulator. This is iindicative of apparent reduction in defect density compared to rf sputtered HfOx.
The work at JSI was focused on Ta2O5-based thin films deposited from precursor solutions. JSI had working on Ta2O5-based thin films from alkoxide-based precursors by Chemical Solution Deposition (for solution synthesis details refer to WP2). Thin films of the ternary composition Ta2O5-Al2O3-SiO2 with the Ta:Al:Si = 8:1:1 atomic ratio were deposited in the temperature range of 300 °C - 400 °C. As reference, pure Ta2O5 thin films were also prepared. The current/voltage (I/V) characteristics of the MIM structures at fields below 100 kV/cm show ohmic behavior, whereas at higher electrical fields, the conduction was governed by the Poole-Frenkel mechanism. Nevertheless it was clear the reduction of the leakage current both when the multicomponent dielectric is used as well as for high processing temperature. Among the samples processed at 350 °C, the Ta one exhibited the leakage current density of 2.3×10-6 A/cm2 at 5V, whereas the 8:1:1 sample showed the lower J value of 8.3×10-7 A/cm2. The samples were also investigated in terms interfacial properties with ZTO oxide semiconductor using metal-insulator-semiconductor (MIS). TFTs were produced using these dielectrics (in collaboration with UNINOVA) and they have been validated to be used in the future in devices to be integrated in transparent circuits and active matrices backplanes.
On other hand TNO has been adapting their dielectric deposition process aiming the project goals. At the moment TNO uses silicon nitride (Si3N4) deposited by PECVD that is being used as reference for large area developments (more details are on WP7 reports).
Finally, FhG-IST has investigated into new candidates for the Ag seed layer, taking both, increase of band gap to minimize the effect of metal induced states, and proper alignment of crystallographic structure into account. The goal was to realize ideal properties of Ag backside mirrors in LED devices via applying a metal oxide seed layer with tailored properties. It was observed that the growth on a thin ZnO:Al layer reduces the resistivity as well as increases the reflectivity of sputtered Ag layers.
Color conversion oxides
The work to done along the project has been focused on the use of ZnO based films, incorporating cerium (Ce) or hydrogen (H). UNINOVA and OSRAM were the partners with deeper involvement on this task. The goal was to use indium free materials and the choice was on ZnO based layers. Two strategies were used: the deposition of Ce doped ZnO and the deposition of ZnO with hydrogen incorporated during the deposition. The former option has revealed that the presence of Ce do not contribute to the luminescence properties at all. This may be attributed to two factors: small grain size and/or high density of defects within the films. The second strategy followed along ORAMA has reveled to be a promising way of improving luminescence properties of ZnO. Indeed the presence of hydrogen seems to passivate the defects within the film.
The introduction of hydrogen during the deposition (strategy developed along the ORAMA project) leads also to highly stable films. Their properties do not change with time (even after one year) or when annealed up to temperatures up to 300ºC. This means they are more stable than other ZnO films reported previously in the literature where hydrogen is incorporated during post-deposition annealing process. In conclusion, ZnO:H has the potential to be further exploited as color conversion layer for LED application.
In conclusion, it one can say that along the project the partners involved in WP5 have established strong collaborative work that resulted in the development and optimization of oxide materials that have fulfilled most of the initial goals established in the DoW, including the deposition at low temperature of indium free oxides that allow for the deposition in plastic substrates, resulting in demonstrators such flexible electronic circuits and active matrix OLED displays.
Work Package 6: Proof of concept for oxides materials for optoelectronics use (CEMOP/CENIMAT, CRF, FhG-IST, OSRAM, TNO, UNIBS, Uni-Giessen)
State of the art lighting more and more uses Light Emitting Diodes (LEDs) in which light is generated in a solid crystal structure, rather than by heating tungsten wires like in incandescent light bulbs or by gas discharge like in fluorescent lamps. This has manifold benefits, like increased life time, high mechanical durability, new design possibilities due to very small form factor and none the less increased electrical efficacy. Over the years LEDs have become the most efficient white light sources competing the established concepts in almost every field of application. Nevertheless the efficacy race is not over now. The optoelectronics industry is highly technology driven and only continuous effort in new concepts enables the European industry to stay competitive.
In the ORAMA project OSRAM Opto Semiconductors and partners have worked on three main concepts integrating oxide materials in LEDs. The concepts deal with different parts of the LED chip. First a mirror that is integrated in modern thin film LEDs and simply reflects light that otherwise would be absorbed in the carrier of the chip. Second a layer that converts part of the blue light to green or red one. Third the light generating interface region itself.
The first concept is that of the so called omnidirectional mirror. Within this, the normally used metal mirror is replaced by an oxide / metal composite mirror, which ultimately increases the reflectance and thus the light output of the LED. Since in thin film LEDs the mirror is not only a reflecting surface but at the same time an electric contact to the semiconductor, a transparent conducting oxide (TCO) has to be used in the new concept. This raises one of the foreseen blocking points of the concept, since the standard method for depositing TCOs (sputters deposition) is known to damage the semiconductor onto which the TCO is deposited. The so called ion damage could be avoided by using other, softer deposition methods for which processes have been developed during the project by the partners TNO (Eindhoven, Netherlands) and FhG IST (Braunschweig, Germany). In work package 6 one task focused on the characterization of the TCOs that have been deposited by these novel methods. With an electrical test vehicle, developed in the beginning of the project it could be shown that the soft deposition methods are capable for a low damage deposition of TCOs.
Optical test vehicles have been developed during the course of the project to precisely measure relevant optical contributions of the oxide layers to the performance of the new mirror. Moreover material parameters as input for a model based approach to the concept could be generated and interface effects could be analyzed using these test vehicles.
In the optical model the test structures as well as the final device has been successfully designed and the model could be used to optimize the layer stacks and the chip design respectively. A significant increase of the light output compared to the metallic mirror could be shown. In an electrical model of the chip the boundaries for the contact and sheet resistances could be evaluated, in which the advanced optical performance is not eaten up by increased electrical loss. In the end, the output from the models has been an optimized chip design of the concept and an increase in wall plug efficiency could be shown. Finally this new chip design could be processed in the OSRAM Opto Semiconductors LED wafer fab in Regensburg, Germany. This is an example of how successful the combination of experimental work and modeling can be integrated to reach a well defined goal.
The second concept deals with the color conversion in thin oxide layers. State of the art technology uses pre sintered ceramics glued to the LED chips for color conversion. The new concept is beneficial to that, since the layer could be integrated in the wafer processing flow and would there for be in a more intimate contact to the chip. Advanced optical as well as thermal properties can be expected here. In the ORAMA project different configurations of the concept have been analyzed and compared within the optical chip model. The potential for increased light output could be shown. In the experimental part of the task the color conversion properties of different TCOs however showed, that the realization of this concept is not around the corner yet.
The third concept is about new light generating interfaces. The current white LEDs use a semiconductor structure made out of a stack of InGaN layers of different composition to convert the electrical current to light. In the new concept so called hetero junctions have been processed and analyzed. In a hetero junction the two partners that come together at the interface are of different crystal structure. In the ORAMA project gallium nitride (GaN) has been combined with different oxides films and nanowires. One of the partners in such a junction is always a p-type material, meaning it is a conductor for holes rather than electrons. Since the oxides used in this task are of n-type nature, the GaN had to play the p-type role. One difficulty with this combination is that the p-type GaN is a bad conductor and therefore can’t be used as a substrate for proper measurements of the hetero junction properties. To overcome this problem special template structures have been produced by OSRAM Opto Semiconductors that have the p-type GaN as the topmost layer and a conducting layer at the bottom. Onto these templates the partners from Universities Brescia (Italy) and Giessen (Germany) have grown the oxide films and nanowires, which make up the hetero junctions. The electro optical analysis of the structures revealed new effects at the interfaces. Both approaches (thin films as well as nanowires) have been successful in generating blue light.
Besides all this technology, another task in work package 6 focused on a design study of lighting used in automobile application. The automotive industry is a major innovation driver in the lighting business. New car models make more and more use of the small size, robustness and long life time of LEDs. New concepts have entered the market showing the enormous design potential of the new light sources, be it interior or exterior lighting. Within the ORAMA project the partner CRF (Orbassano, Italy) integrated LED lighting in plastic glazing. This concept shows the potential design of a lightweight part produced by molding processes. The reduced weight is essential for achieving future goals of fuel efficiency.
It can be concluded that in work package 6 of the ORAMA project new concepts for the use of oxide materials in optoelectronic devices could successfully be proven. The achievement of goals based mainly on two important ingredients. First the close collaboration of the related partners and second the iterative combination of the model based approach with the experimental results. During the course of the project new methods and processes have been established that are of great value for the ORAMA partners. Moreover the results of the different tasks are going to be exploited in further internal as well as collaborative projects.
Work Package 7: Proof of concept for oxides materials for electronics use (AO-Action CEMOP/CENIMAT, CRF, EKUT, FhG-IST, FORTH, TNO, UNIBS, Uni-Giessen)
Highlights in terms of outcome of work package 7 in the ORAMA project are directly linked with the developed materials in the previous work packages and three demonstrators of Platform 3, as was decided in the mid-term of the project. In summary the ORAMA consortium was able to demonstrate the three working prototypes:
• Demo #1: Steering wheel application with switches and reconfigurable icons
• Demo #2: Multifunctional glazing
• Demo #3: p-type gas sensors
In the following sections the main achievements, outcome and highlights are described in the detail such a short synopsis allows for.
Oxide materials for electronic use
With respect to displays it is evident that a light-emitting (except color changing) unit is required. Consequently, one also needs integrated into the display (transparent) electronics which allows an individual control over pixels forming all sorts of images. Basic elements are transistors realized in thin film technology (TFT), both n-type as well as p-type. As not all specifications can be listed here, some selected ones shall be highlighted: to get rid of the dependence on Indium-based materials alternatives were synthesized and tested. Zinc-Tin-Oxide (ZTO) layers were found to be very performant and could be used on both flexible substrates (polymer-based, therefore temperature limited) as well as rigid substrates (glass-based). An example of key performance indicators for n-type oxide TFTs are
• compatible with flexible substrates (maximum T=150 °C), providing µFE≈4 cm2/Vs, Von≈ 4 V and on/off>108 on Si/SiO2 substrates;
• high performance, for rigid substrates (maximum T=300 °C), providing µFE≈15 cm2/Vs, Von≈ 1 V and on/off>108 on Si/SiO2 substrates.
A lot of the work was focused on solution processing of the TFT in order to reduce the processing temperature as much as possible. As it could be demonstrated the homogeneity over a wafer scale and the reproducibility from wafer to wafer was within the specifications and sufficient to encourage the partners in continuing even after the end of the funding period. Also the possibility of patterning of TFT arrays and interconnects for mass production is given.
p-type oxide materials for chemical sensing
n-type oxide materials are currently dominating the market of chemical metal oxide gas sensing. Here as well ORAMA advanced the knowledge in the field by focusing on p-type oxide materials. Quite a number of promising materials were synthesized and screened and while it turned out that Co3O4 strongly responds to alcohols, acetone and larger hydrocarbons, it also shows a good response to CO and H2S in dry conditions and hardly any to lower hydrocarbons e.g. methane, ethane. The sensor signals of Co3O4 decrease in general with humidity. However, the resistance values themselves are humidity independent over a large temperature range for certain test gases. Furthermore, CuO and a CuAlO2 were investigated. Also NiO thin films deposited by sputtering from a NiO target were selected for the detection of ozone and have been tested as thin films deposited in in 0 % 10 % 25 % 50 % O2 at 200°C deposition temperature. Finally CuO nanowires by thermal oxidation of CuO thin films were investigated for gas sensing both by measuring variation of electrical resistance and by measuring work function changes as a function of pollutant gases. The devices were showing signals towards butanol at various working temperatures, from 150°C to 400°C.
Proof of concept for electronic functionalities
One of the ultimate goals was to make a flexible AM OLED display. OLED displays have more stringent requirements when it comes to TFT performance. To develop system-on-panel capability row drivers have been demonstrated using the same materials / technology as described above already.
The mechanical equipment for fragmentation test and bending test has been built up. Firstly, Crack Onset Strain (COS) measurements were taken on the flexible system. From this test, the critical mechanical load which can be carried by the system in the form of tensile stress has been revealed. Secondly, the measurements of the TFTs on the foil were performed in the bent and bent-strained state. The form of the curvature is defined by different radius of 2 to 10 mm.
During the ORAMA project it was demonstrated that the measurements of transistor at the bent and strained states can be successfully measured on the built up equipment. However, to improve the understanding of the influence from mechanical loading on the foil, more statistically measurements are still required.
In conclusion, it was demonstrated that the implementation of Indium-free semiconductor in flexible AMOLED displays, proved the inherent flexibility of the TFT backplane to high degrees of strain with minimal variation in performance, and the integration of these TFT in a large portion of the requisite thin film circuitry required for real product implementation.
Proof of concept for circuit integration
The main objective in this section was to demonstrate the feasibility to produce logic circuits based on the materials and thin-film transistors (TFTs) developed within ORAMA, both in nMOS and CMOS architectures. After the first demonstration of an oxide CMOS inverter based on IGZO and SnO semiconductors, it was possible to use transparent indium-free oxides (electrodes, semiconductors and conductors) deposited by sputtering without intentional substrate heating and to use low cost, transparent and flexible substrates. For this end, the TFT technologies, were employed to obtain inverters on flexible substrates based on improved processes for: ZTO (n-type semiconductor), SnOX (p-type semiconductor), SiO2/Ta2O5-SiO2/SiO2 (dielectric) and GAZO (electrodes).
Besides sputtering processes, which are to date the most suitable for high performance oxide thin films, solution-based processes, namely spin-coating of Ta-based dielectric layers were also evaluated for unipolar circuit fabrication, by combining these layers with sputtered ZTO or GIZO semiconductors.
The project design of ORAMA has always respected the material development and test principle but right from the beginning of the project it was decided to produce a number of demonstrators based upon the different materials. These demonstrators should on the one hand allow an identification of the potential of the material development and on the other hand be used as “show and tell” to a wider community.
Demonstrator #1: Steering wheel application with switches and reconfigurable icons
Steering wheel applications with switches and reconfigurable icons are particularly suited for applications such as automobile instrument panels where large displays and controls are desirable to provide a wide range of information, with minimal driver distraction and the safe input of data to vehicle subsystems or for communication based activities. The solution replaces traditional switches, knobs, sliders and buttons with capacitive electronics. All the functions of regular switches are therefore controlled by typical touch interactions like taps, swipes and pinches, depending on the operating control.
There are also inherent advantages related to switches and reconfigurable icons applied to steering wheel and automobile instrument panels: the most important benefits are listed below:
• High perceived quality
• User friendly HMI (comfort)
• Functions/controls integration
• High luminance
• Better managing of the optional buttons
• Easy integration required.
Reconfigurable and autonomous icon/logo device to be integrated into interior plastic component as dashboard and interior trims can replace standard dashboard systems in the near future.
Several customers are identified (both Tiers 1 of FGA for door panels and other transportation makers and PCMA plastic interior components manufacturers). These companies are potentially interested in this technology because it offers several benefits such as:
• Reconfigurable icon/logo to be set on-demand by customer
• Autonomous device (no cabling)
• Thin lightweight film which allows discrete not flexible components
• Integration platform suitable for many different automotive applications
Breakdown in materials used in cars (2000-2010 C segment) – 14 % in weight of plastic around 40 % into interiors with related impact to SMART-EC. Although up to 13 different polymers may be used in a single car model, just three "families" make up some 66 % of the total plastics used in a car: polypropylene (32 %), polyurethane (17 %) and PVC (16 %).
A crucial step in technology transfer is the identification of the position in the value chain of these companies in order to clearly propose to final end users the right suppliers.
Demonstrator #2: Multifunctional glazing
Transparent coatings offer several opportunities in automotive sector for both direct (application on glazing) and indirect (integrated in functional devices) applications. Already for several years major glass manufacturers have used functional coating on windows such as electrically conductive, IR absorbing/reflecting as well as antireflective and hydrophobic coatings with interesting results. However, one drawback was the cost. Innovative materials developed with improved functional properties need to be made available at a lower cost in order to be competitive. Moreover, the introduction of plastic glazing, an aspect extremely important for reducing the weight, requires specific deposition parameters which are suitable for high performances coatings.
The reduction of weight is a very important goal for automotive companies: the need to reduce the vehicle’s mass by 10 % by 2020 both in EU and US. The use of light-weight materials such as plastic glazing is becoming of great interest topic.
Generally speaking, plastic glazing provides us with greater freedom to create the distinctive and desired window shape and can improve fuel economy of the vehicle. In Fiat 500L, for instance, replacing glass for fixed rear quarter windows (RQW) by plastic glazing represents a great opportunity in reducing weight by up to 1,5 kg: considering that 10% weight reduction leads to 3.5 6.5 % CO2 emission reduction per km (“Possible regulatory approaches to reducing CO2 emission from cars”, IEEP, CE, TNO, Dec. 2007), RQW weight reduction leads to approx. 0.1 gCO2/km. If the entire glazing were substituted with plastic solutions, then up to 20kg should be saved, leading to reduction of ~1.5 gCO2/km. Nevertheless, it has to be noted that said substitution has to be made economically sustainable: other functionalities have to be integrated in order to reduce the amount of parts and, then, costs (for instance, in Fiat 500L also some aerodynamic content was integrated into the RQW). In the mid to long term, further integration can be explored, for instance roof spoiler, pillars cladding, 3rd brake light and optics, rear wiper foot, handles, logos, as well as a de-frosting system with appropriate coatings to improve wear resistance.
This rear fixed side window is made of plastic (polycarbonate) by using a two-shot injection compression molding, which allows for the seamless integration of an aerodynamic spoiler. In order to demonstrate the possibility to increase the integration of functions, in the same component the lighting by LEDs application was introduced. The results generated by ORAMA in the deposition materials and process will be exploited in the multifunctional coatings for the plastic component making it at the same time protected by UV, anti-scratchable and heatable.
In terms of exploitation, important stakeholders for this application (as demonstrated by their history in plastic glazing application), showed a clear interest in transferring samples and doing some integration tests using ORAMA background and foreground knowledge.
In the same direction also the materials and technology providers were really interested to get information about the project status and output. Amongst them there are leading companies in plastic materials production: polyolefins, polycarbonate and blends. Partially those companies are also very active in polycarbonate production for plastic glazing providing tier 1, not only the optimized material but also processing: surface treatments, injection moulding, in-mould labeling.
Demonstrator #3: p-type gas sensors
p-type gas sensors have not been explored widely in the past. Based upon theoretical considerations one can demonstrate that their sensor signals are typically the square root of the corresponding n-type-ones smaller. But on the other hand there are also inherent advantages related to p-type-sensors where the most important is the reduced operation temperature. This gives some operational benefit such as
• lower power consumption, consequently potential of battery operation
• applicability on “unconventional” sensor substrates such as plastic materials
For the implementation of the sensor demonstrator three materials were chosen, which showed the best responses to the above mentioned target gases: Co3O4, CuO, and ITO. Those materials were drop-coated as a paste of each metal oxide mixed with xylol, butanol, and Tween 80 on flexible substrates with interdigitated electrodes and heaters of 300 μm x 300 μm size.
In terms of exploitation one has to highlight that low power operation of gas sensors makes it possible to switch from mains operation to battery operation. If one is just looking into the classical field of gas alarms one can identify two main areas:
1. Gas alarms for burnable gases and explosion prevention
2. CO alarms for preventing from intoxication
Considering the market size it makes sense to check different sources of information. Data on new market trends released by Honeywell Company City Technology (UK) in August 2013 shows extensive growth in the Industrial Gas Detection sector, which has now reached $2.2 billion in worldwide revenues. The biggest growth in the sector has been attributed to the oil and gas industry, spurred on by a surge in shale gas exploration and the increasing demand for energy. John Warburton, Strategic Marketing Manager at City Technology, describes this market as vibrant with many opportunities for continuing growth. "The Gas Detection market is very strong at the moment. For example, we are predicting that the global demand for gas sensors will grow at 5 – 6 % pa over the next five years with the Asia Pacific region growing at 10%. Growth in North America will remain strong, driven by the on-going development of shale gas deposits. “Moreover, new trends in Gas Detection go beyond traditional markets. For example, City has highlighted the growth in the market for Medical and Domestic Gas Detection sensors, for instance in carbon monoxide and flammable gas alarms, which are worth nearly $90 million combined." John Warburton affirms that, “These future growth markets are being driven by health and safety awareness and legislation. Furthermore, it will be an increasing demand for energy and the strengthening global economy that will shape these developments and, therefore, the future of gas detection.”
Handheld/portable gas detection equipment represents the largest and the fastest growing segment. Growth in the segment can be attributed to a range of usage benefits that portable gas detection equipment come with, such as their compact size, simple usage pattern, and ability to provide uninterrupted monitoring services. Greater reliability and lesser false alarms are other critical factors that are influencing the growing demand for handheld/portable gas detection equipment.
A part of this potential can be served in the future by sensors based upon p-type-materials developed within ORAMA.
Work Package 8: Exploitation, training and knowledge transfer (AO-Action CEMOP/CENIMAT, CRF, EKUT, FhG-ISC, FhG-IST, FhG-IWM, FORTH, JSI, Soleras, TNO, UNIBS, UNICAM, Uni-Giessen)
WP8 is oriented at monitoring and promoting exploitation of results, management of the Intellectual Property Rights (IPR), and Knowledge Transfer including:
• exploitation all scientific results of the project towards automotive sectors and other emerging high impact fields as flexible electronics; this will be achieved by means of proper management of IPR;
• management of knowledge transfer inside/outside the consortium by means of traditional and innovative tools to exchange knowledge between specialists and to facilitate the implementation of the developed materials and technologies into industrial environments;
• exchange knowledge between scientists and to elaborate a training programme (summer schools, courses, seminars) for formation of specialists in materials science and integration in final devices.
This WP consists of 4 tasks concerning Exploitation Plan & Technology Transfer, IPR Management, Dissemination of results and Training & Education.
Within Exploitation Plan & Technology Transfer task all ORAMA partners are involved in the exploitation strategy with different final perspectives; in the first year of the project an Exploitation Strategy Seminar was followed by all partners in order to use a common way to transfer technical results from each work package to potential use of them from universities and research institutes and from companies. The final full list of results is shown below (Section B, Part B2).
All these results were characterized in order to get a simplified business plan for future exploitation actions. Among the different exploitation activities, connections with tier 1 and tier 0 is a crucial step for automotive applications.
Concerning IPR management task, CRF performed in the last year a very important patent search to retrieve published patent documents relating the specific solution: PLASTIC GLAZING FOR AUTOMOTIVE.
Within the context of the Orama project, Soleras Advanced Coatings developed a novel sputter target for a new family of n-type active semiconducting oxides, namely (Ga)Zn Sn Oxide. This target can be offered as a large single-piece oxide part, thereby eliminating the problems from attaching smaller individual target pieces for larger areas. In particular, the target can be offered as a rotatable target, thereby having benefits of large area uniformity, higher target utilization and higher sputter rates over conventional planar targets. This translates in lower material and operating cost for the coating manufacturer and, ultimately, lower cost of the display. This is achieved with a new thermal spray manufacturing process for this material, instead of sintering. Below are the details of patent submitted within Project (Section B, Part B1).
The objectives of dissemination task are to communicate and deliver knowledge about the Orama project results and achievements by using the appropriate channels to the various interested stakeholders. The web site (http://www.orama-fp7.eu) is continuously updated with the latest information on literature, presentations and conferences as well as the preparation of an Orama newsletter. Another effective way for disseminating information about the project activities and results is the regularly published newsletter. Three newsletters have been published:
• The first newsletter reported on the just very successfully completed second summer school where AO Action conducted interviews with participants (one lecturer and one student) on location to get an impression of their experience. Vito Lambertini (CRF) provided an insight into the future of smart materials in the car industry and Rodrigo Martins (UNINOVA) presented the materials science perspective in his role as president of the EMRS.
• In the second newsletter the focus was shifted to project (infra) structure, again highlighting summer schools as an important tool for dissemination and training of future scientists in the field of new materials and oxide electronics. Jan Gäbler (Fraunhofer) from the coordination team presented some of the challenges involved in coordinating a large-scale IP like ORAMA while Brian Cobb (TNO) in an interview conducted by AO Action revealed some of the incentives for a research institution to participate in EU-funded projects.
• The focus of the third newsletter will be on the demonstrators, showcasing the variety of exploitable technologies developed within the framework of the ORAMA project. This last newsletter should also function as a document to deliver the final results and achievements of the ORAMA project.
The task of Training and Education is dedicated to delivering knowledge with high level of education formats. Three ORAMA summer schools were organized during the project.
Work Package 9: Scientific management (FhG-IST)
The project was coordinated by Mr. Dr. Volker Sittinger, Fraunhofer IST. Several Boards have been installed:
• Governing board, comprising one responsible person at every benefiary, responsible for major decisions, meets 6-monthly during the General Assemblies
• Steering committee, consisting of the ten work package leaders, responsible for the scientific progress, meeting monthly via web-conferences
• Industrial Advisory Board, consisting of three industrial end-user companies
General Assemblies have been performed 6-monthly to review the results and to discuss the next steps. They took place mostly at partner places so that the consortium could visit the laboratories. The results of the project were presented towards the Commission in three Review Meetings after each reporting period.
A project handbook has been edited to distribute all management procedures to the participants. It has been updated four times during the project lifetime. The web-based project management software EMDESK was used as a common database for all reporting data and for documents as well.
Two amendments of the Grant Agreement have been filed during the project duration to react on changes in the consortium.
The project website www.orama-fp7.eu was hosted by Fraunhofer and updated regularly. All project publications are listed there to inform the broad public.
Work Package 10: Scientific management (AO-Action, CEMOP/CENIMAT, CRF, EKUT, FhG-ISC, FhG-IST, FhG-IWM, FORTH, JSI, Soleras, TNO, UNIBS, UNICAM, Uni-Giessen)
The objective of this WP was to maximise the effectiveness of the Orama work programme delivery by developing detailed scientific and technical plans – Action Plans - for each task on an annual basis. This allowed the interactions between tasks to be identified and coordinated and resulted in project roadmaps that were continuously updated and consolidated via: steering committee meeting and all main set of actions envisaged in the six main technical work packages. Moreover IPR actions, besides the one already promoted by the partners integrating this consortium, were taken into account and will be mentioned also in the present document.
Those activities were performed and as well as others to disseminate the project results, not only through the academia but also to the policy makers. Through the intervention of this task coordination, symposiums have been organized at European Materials Research Society (EMRS) meetings and it is expected to have new proposals for future EMRS conferences. The results of ORAMA have also been deeply disseminated in Transparent Conductive Materials (TCM) conferences.
Moreover, it has been promoted within the European parliament actions where ORAMA appear as sponsor (see report from the coordinator). Apart from that, the ORAMA has been also disseminated in actions taken at E-MRS such as Europe in motion (see report of the coordinator) as well within workshops organized by the European Commission where Professor Rodrigo Martins was present to establish the next SETPLAN for materials.
It should be worth to notice that ORAMA has been fully disseminated in European networks materials related such as: Matval (Alliance for materials - a value chain approach to the materials research and innovation - MatVal); A4M (Alliance for Materials platform).
As all technical activities have been accomplished according to the amendment and corresponding plans proposed, where all main milestones and deliverables were realized. In the following we will concentrate in a overall scientific appreciation of the project results, as well as in evaluation the outputs of the project concerning education, training and promoting summer schools.
Evaluation of the ORAMA scientific activities (Dissemination and Communication of Scientific Actions)
As far as science is concerning, overall we have at least 273 reported dissemination actions (112 publications in peer reviewed journals and 161 attendances in scientific meetings and conferences).
The 112 reported publications in four years are equitably distributed during the project. The set of papers published in scientific journals with impact factor above 3.5 is 35 % only 14 papers (13 %) where published in journals without impact factor at web of knowledgement. It is also relevant to notice in which areas the publications were performed. From the analysis we conclude that all main areas addressed by ORAMA were covered and so, the ORAMA under this point of view can be considered a success story. We have also to point out that still a set of papers submitted for publication, which will raise these values.
We would like to emphasise that a book was published at Wiley (Pedro Barquinha, Rodrigo Martins, Luis Pereira, Elvira Fortunato, Transparent Semiconductors: From Materials to Devices. West Sussex: Wiley & Sons (March 2012), ISBN 9780470683736) whose all four authors have been involved at ORAMA and deals with the main subjects project related that has been so far a tremendous dissemination worldwide taken by the number of purchases and because the book editor is making the third edition of it. Apart from that we have also to mention that also the ITC 2012 was chaired by E. Fortunato, involving in the organizing board members of ORAMA (P. Barquinha, R. Martins and A. Nathan) from which a publication at Journal of Display Technology was done (E. Fortunato, J. Jang, P. Barquinha, A. Nathan, and R. Martins, Editors of the Special issue on the 8th International Thin Film Transistor Conference (ITC 2012), forward message, J. of Display Technology, 9 (9) (2013), pp. 687).It is also relevant to highlight that about 20% of the papers published corresponds to joint involvement of more than one partner. Also worthwhile to notice the special issue of Thin Solid Films published by G. Kiriakidis et al, where the focus was also centred in advanced functional oxides for electronic and energy applications (G. Kiriakidis, International Symposia on Transparent Conductive Materials, October 2012 Preface, Thin Solid Films, Vol, 555 (2014), pp. 1-2, preface).
Finally a book chapter was also published (P. Barquinha, R. Martins and E. Fortunato, “N-type Oxide Semiconductor Thin-Film Transistors” in “Advances in GaN and ZnO-based Thin Film, Bulk and Nanostructured Materials and Devices”, ed. by S. Pearton, Springer Series in Materials Science, Vol. 156 (2012)., pp 435-473, ISBN 978-3-642-23520-7) connected to the scientific findings along the ORAMA project.
Another noticeable pointed to be taken into account is that the area related to materials development, modelling and process represents more than 53% of all papers; 16% has to do with the evaluation of materials properties and 22% correspond to devices, used as the tester of the proof of concept, where materials could be integrated. Here all expected testers were developed and the scientific results achieved turned public via journal or presentations.
Moreover, dialogue was also established with industry, policy makers and other stakeholders by promoting selective debates, either in the European Parliament or in specific ambient for which stakeholders were invited. As highlight we mention the Workshop organised in the European Parliament and the meeting in Paris with industry and institutes interested in the ORAMA results, exploited by the scientific coordinator, or the presentations done by the project coordinator for various stakeholders in Europe (see for instance the presentation in the spring EMRS 2013 conference http://www.emrs-strasbourg.com/index.php?option=com_content&task=view&id=795&Itemid=999 or in international conferences worldwide.
The impact of the ORAMA is also measured by the number of presentations given by the coordinator and the scientific coordinator as invited or plenary talks in major worldwide conferences materials, technologies and devices related, besides the ones performed by all experts and workers project related. It is real impressive to see that at least 161 presentations were performed, from which 25 as plenary talks (16 %), and so for quite large audiences (from 300 to 3000 attendees); 89 invited talks (55 %) in major specialised symposia; 19 as normal oral communications in workshops and symposia (12 %) and only 28 poster presentations (17 %). It is also relevant to know in which field the presentations were performed. Overall we have had 47 presentations related to Materials (26%); 42 presentations related to Technology and processes (23%); 36 presentations related to devices and systems (20%); 25 presentations (14%) targeting the use and incorporation of materials in different sectors (multipurpose); 17 presentations related to Modelling/simulation (9%); 15 presentations (8%) related to transport properties of materials and devices. Again we notice that relevant fields in which ORAMA has performed his activity were fully filled and so accomplished the scientific mission as far as scientific data communication and dissemination are concerned.
When promoting scientific dissemination, we should also look for citizens and it is also very important to notice that about 7.5% of all presentations were given in the mother language of the partners (not considered English), which is a way to get closer to standard citizens. By doing so, we are real promoting science and technology for all people, not the ones with high education level, inline what the commission expected in this area.
Organisation of Scientific Events
ORAMA is in the leading edge of the todays science and technology developments, translated not only by the International recognition of having members of the consortium involved in worldwide events related in outcome actions as the one to be taken in Japan: Materials Frontier for Transparent Advanced Electronics (http://www.mrs-j.org/meeting2014/en/prg/index_s.php?id=s20) where P. Barquinha is involved, but also because the concept is now fully accepted by all as can be taken from the set of recent events organized under the flagship of transparent electronics, a concept brought to the field by members of the present consortium and where it exists now a consolidated view of the potential market (http://finance.yahoo.com/news/global-transparent-electronics-market-2014-164800694.html).
One must strong emphasise the set of workshops promoted by G. Kiriakidis each two years in Crete/Greece where the best worldwide experts in the field are invited to be present and were partners from ORAMA has been always involved, not only in the organizing committees but also delivering plenary/key note speeches or invited talks (http://www.tcm2014.org/). In 2014 the event took place from 13-17 October 2014 in Platanias-Chania, Greece.
Worthwhile also to notice major events organized by the members of the present consortium like the E-MRS 2011 Fall Symposium I: Advances in Transparent Electronics, from Materials to Devices III (http://iopscience.iop.org/1757-899X/34/1/011001); ITC2012 (http://eventos.fct.unl.pt/itc2012); or where members of ORAMA belong to the scientific organizing board. As example, we will supply the ones which the scientific coordinator of ORAMA project was involved: The International Advisory Committee for the Energy Materials, Nanotechnology, EMN Fall Meeting taking place at Orlando Florida, USA from Nov. 22 to 25, 2014 (http://www.emnfall.org/2014/); International Advisory Committee of IUMRS-ICA2014, held from 24th (Sun.) to 30th (Sat.) August 2014 at Fukuoka University, Japan, organized by the IUMRS Japan and hosted by the Asian MRS Asian Members (http://10times.com/iumrs-ica); International Advisory Board of Symposium FH “Recent Developments in the Research and Application of Transparent Conducting and Semiconducting Oxides” of the 6th Forum on New Materials (June 15-20, 2014), CIMTEC 2014, Italy (http://www.cimtec-congress.org/index.php); International Advisory Committee of the International Conference in Asia – 2013, to be organized under the International Union Materials research Society, IUMRS-ICA-2013, (http://iumrshq.org/index.php?option=com_jevents&task=icalrepeat.detail&evid=481&Itemid=65&year=2013&month=12&day=16&uid=5dcc6394c9221eb54f1ab6e59323860b) held from December 16-20, 2013 at Indian Institute of science, Bangalore, India; International Advisory Committee of International Conference in Advanced Materials, IUMRS-ICAM2013, Qingdao International Convention Center, China, Sept. 22-27. 2013 (http://www.iumrs-icam2013.org/en/#); International Advisory Board of ICANS 25 (http://www.icans25.org/) August 18–23, 2013 Toronto, Ontario Canada; 7th International Conference on Materials for Advanced Technologies, ICMAT 2013, 30 June to 05 July, 2013, Singapore (http://www.mrs.org.sg/icmat2013/public.asp?page=home.asp); Oxide-based Materials and Devices Conference, Part of the SPIE International Symposium on Integrated Optoelectronic Devices 2012 (conference 8363), January 22-25, 2012 San Francisco, CA USA (http://spie.org/x2584.xml); 4rd International Symposium on Transparent Conductive Materials, TCM2012, October, 21-25 2012, Crete, Greece; Member of the International Advisory Committee and chair for the “International Conference of Young Researchers on Advanced Materials (ICYRAM 2012)” Organized by the Materials Research Society of Singapore in association with NUS and NTU, 1st – 6th of July, 2012, at Biopolis, Singapore (http://www.mrs.org.sg/icyram2012/public.asp?page=home.asp); Int. Conf. on Amorphous and Nanocrystalline Semiconductors, since 1999 (biannual: ICANS 2011, http://asia.iop.org/cws/article/news/47151); Organized program committee, SPIE West, Oxide-based Materials and Devices II, S. Francisco, USA, 23-28 January 2011. All this clear prove the scientific excellence of what ORAMA promoted.
Orama’s objectives are to develop new oxide materials and associated processes which offer device developers new possibilities. The three key issues which Orama addressed were:
Orama consortium has developed materials and processes compatible with flexible polymer substrates. A range of flexible displays with touch functionality have been developed. This will be enforce new products with touch functions even on temperature sensitive surfaces like textiles, smart cards, etc.
The use of the metal oxide thin films developed in Orama, which have electrical functionality combined with transparency, lead to exciting possibilities for developers of human computer interfaces.
Orama has initiated the development of ink-jet non-fab processes which are significantly more energy efficient than current processes performed in semiconductor fabrication facilities with high-class cleanrooms. Multi-component metal oxide semiconductors free of Indium and other scarce or hazardous metals were developed and tested for optoelectronic properties. These oxides will be used to substitute state of the art vacuum processes in the future.
The robust modelling of materials, processes as well as devices has built the foundation for the project. The modelling on multiple scales concerning the microscopic structures of the desired materials, leads to the possibility to neglect or promote different routes, which helps to speed up the development. Similarly the developed process models have shown that prototyping for coating processes is possible and this accelerates also the implementation of deposition systems. Last but not least the device simulation helps to optimise the electronic circuits before their production. This step brings down the costs and time of experimentation, prototyping and optimizing device performance.
The developed oxides impact on the devices applications:
(i) In flat panel display industry the usage of abundant, inexpensive oxide materials for the TFT backplane has been demonstrated.
(ii) The traditional switches, knobs, sliders and buttons with capacitive electronics can be replaced in future with the combination of the developed touch and display devices. All the functions of regular switches are therefore controlled by typical touch interactions like taps, swipes and pinches, depending on the operating control. A special application for automotive industry was demonstrated in form of a reconfigurable icon. This stands as an example for a touch based control activity for various internal and external car functions in future.
(iii) CMOS inverters based on indium free oxides were demonstrated which show the capability for further logic circuits on flexible substrates.
(iv) New p-type materials for gas sensing applications were developed for low-concentration gas detection at lower working temperatures. This offers the possibility of extending these sensors on flexible substrates in future.
(v) These developed materials and processes open a new window for higher efficiency at lower costs in solid state lighting as an integral part of the information and communication technology.
As already mentioned, during the project several actions were promoted at the European parliament where ORAMA appeared as sponsor, as well within workshops organized by the European Commission where Professor Rodrigo Martins was present to establish the next SETPLAN for materials. ORAMA has been also fully disseminated in European networks materials related such as: Matval (Alliance for materials - a value chain approach to the materials research and innovation - MatVal); A4M (Alliance for Materials platform). Apart from this, the impact of ORAMA can be also evaluated by education and training action that have been promoted along the project.
As far as education is concerned it has been promoted international schools connected to the scientific and technical concepts developed within ORAMA, to which we would like to notice the ERASMUS SCHOOL ON “Transparent Electronics: From Materials and Devices to Circuits and Systems", that by the second consecutive year took place in Chania Crete, this year was on 7 - 20 July 2014. (http://transelect.chania.teicrete.gr/Organize_Comitee.php) where experts from ORAMA (E. Fortunato, L.Pereira and G. Kiriakidis) have been involved.
Also internationally, the involvement of the scientific coordinator (R. Martins) in international committees devoted to disseminate the leading edge of science and technology worldwide for young students (International Conferences of Young Researchers on Advanced Materials, ICYRAM, see above), turn possible to introduce the matters related to transparent electronics, especially the ones mentioned in the Wiley book whose authors are member of the consortium that it is used during such actions that already took place in Singapore, Taiwan, Japan and the next well be in China. Also similar actions are already programmed to take place in Korea, Singapore, India and Vietnam, from 2015 tom 2017.
Apart from that, it is noticeable the introduction of the transparent electronic topic in the Portuguese PHD programmes of Nanotechnologies and Nanosciences (http://www.dcm.fct.unl.pt/ensino/programas-doutorais/doutoramento-em-nanotecnologias-e-nanociencias) as a discipline and the use of scientific and technical contains, such as the new findings related to physical and chemical process routes, functionalization of materials for a plethora of device and product applications, going from energy to health applications, were introduced on related disciplines given in the integrated master course in Micro and Nanotechnologies of the New University of Lisbon (http://www.fct.unl.pt/candidato/licenciaturas-e-mestrados-integrados/mestrado-integrado-em-engenharia-de-micro-e-nanotecnologias) where we would like to highlight the introduction of the technologies developed within the contain of the microelectronics disciplines (3 disciplines related). The concepts of advanced oxides for electronic and optoelectronic applications were also introduced in PhD programme of Materials Engineering (http://www.dcm.fct.unl.pt/ensino/programas-doutorais/doutoramento-em-engenharia-de-materiais) as well as in the Master course of Materials Engineering (http://www.fct.unl.pt/candidato/licenciaturas-e-mestrados-integrados/mestrado-integrado-em-engenharia-de-materiais).
Moreover, at Portuguese national level was launched in 2013 a PhD program in Advanced Materials and Processing (AdvaTech), supported by the Portuguese National Science and Technology Foundation, involving 8 public Portuguese Universities and 12 research labs, coordinated by R. Martins, where the scientific and technical public disclosed achievements at ORAMA were introduced in the set of lectures to be given, going from advanced materials for energy, electronics, biotechnology and manufacturing/processing, as cross cutting component of their education and to show how materials are real an enabler of all technologies: (https://www.ubi.pt/Noticia.aspx?id=5055; https://fenix.tecnico.ulisboa.pt/investigacao/IST-NM/lateral/ensino/programa-doutoral-em-materiais-avancados-e-tecnologias-de-producao; http://www.cenimat.fct.unl.pt/news/2013/12/abertura-de-concurso-programa-doutoral-advamtech-1-edicao-2014; http://www.ua.pt/PageCourse.aspx?id=386; http://apps.uc.pt/courses/PT/course/4941; http://www.fct.unl.pt/noticias/2014/09/programa-doutoral-em-materiais-e-processamento-avancados-advamtech).
we also would like to pointed out that the topics of advanced functional oxides was introduced in the PhD programs in University of Galati, to which International Board accounts with R. Martins. The same was also promoted close to the International Master Program in Functional Advanced Materials & Engineering funded by the ERASMUS MUNDUS Program of the European Union, offered in English by 7 universities of 4 different countries (Grenoble INP and U. Bordeaux in France, U. Augsburg and TU Darmstadt in Germany, U. C. Louvain and U. Liège in Belgium, and U. Aveiro in Portugal), FAME in which R. Martins is a member of the External Quality Advisory Board (http://www.emmi-materials.eu/). This program is run by Institutte of materials of Bordeaux and was renewed until 2016.
Similar efforts were made by G. Kiriakidis within FORTH, aiming to disseminate the ORAMA achievments towards the education Greek programs, especial in the area of Heraklion, Crete. JSI is also pushing similar actions within Slovenia.
As training actions we have to notice the on-going activity within each partner labs belonging to Academy concerning training of personnel involved in Master thesis related to the topic as well in the on-going activity of the PhD thesis. This a considerable gain for the European institutions involved. As examples, we will pointed out the activity related and on-going in Portugal, where we have 22 Master thesis run since 2011 whose focus was in Advanced Functional Oxide materials and whose supervisors were members of ORAMA project as P. Barquinha, L. Pereira, P. Martins and E. Fortunato. In the same period we have had 18 PhD students involved in activities related to the ORAMA achievements, that are training in the processes developed as well as in building different blocks on novel devices and systems, where the gain obtained from ORAMA is of vital relevancy for their activities.
Apart from this concrete and almost ergonomic action, taken by all partners from the scientific community, from which we have over 70 master students and over 50 PhD students, involved in activities related to the ORAMA main scientific and technical achievements, we have to concentrate in broad training activities that will be maintained after the closing of the present project.
It is so relevant to notice how actions will be promoted after the end of the ORAMA project. In a consistent way, training and tutorial actions are foreseen to be taken by the European Materials Research Society, during their annual fall and Spring meetings (http://www.emrs-strasbourg.com/). Also similar actions are have been already taken by the TCM set of workshops, organised every two years in Crete (http://www.tcm2014.org/).
Apart from that, Uninova lends short training courses for technologists working in other research institutes or in development areas of the industry, devoted to Advanced Functional Materials where the know-how gained within ORAMA is of great relevancy to be in the frontline in Europe and worldwide in such type of activity.
Other partners from the Academia are also introducing in their educational systems the novel scientific achievements brought to the present state of art by ORAMA.
Promotion of Summer Schools
First of all we have to pointed out the realization of 2 summer schools performed in different environments, Greece (http://www.printedelectronicsworld.com/articles/tcm-2012-4th-symposium-on-transparent-conductive-materials-00004853.asp?sessionid=1) and Lille (http://www.emrs-strasbourg.com/index.php?option=com_content&task=view&Itemid=1568&id=796) incorporated respectively in the Transparent Conductive Materials workshop and the E-MRS spring meeting, where we have had the opportunity to open the scientific achievements towards the young research community worldwide. Moreover, we also organize a symposium within E-MRS aiming to promote high level scientific discussion of ORAMA achievements (http://www.emrs-strasbourg.com/index.php?option=com_content&task=view&Itemid=142&id=423). Apart from that, we successfully promote the scientific dissemination via the webpage and the newsletter that was distributed through major events related to the topic areas tackled by ORAMA, such as Advanced Materials (in all E-MRS and MRS conferences, from 2011 to 2014, and from 2013 to 2014 in all IUMRS major events, especially the ones located in Asia); Sensors (in conferences topic related); displays (SID, IdTex, MID); thin film transistors (ITC); growth processes (SVC), materials for energy (ICANS), among others, tackling not only Europeans but the worldwide broad community of users of materials for multipurpose.
List of Websites:
Grant agreement ID: 246334
1 October 2010
30 September 2014
€ 13 355 499,38
€ 9 742 506
FRAUNHOFER GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Deliverables not available
Grant agreement ID: 246334
1 October 2010
30 September 2014
€ 13 355 499,38
€ 9 742 506
FRAUNHOFER GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Grant agreement ID: 246334
1 October 2010
30 September 2014
€ 13 355 499,38
€ 9 742 506
FRAUNHOFER GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.