Final Report Summary - HITECA (technology development and fabrication of HIgh TEmperature high frequency CApacitors for power switch integration) Executive Summary:The objectives of the HITECA project was to fulfil the specific technological challenge of Call JTI-CS-2013-03-SGO-02-087 entitled “Technology development and fabrication of high-temperature high-frequency capacitors for power switch integration”.HITECA team members have previously investigated a range of lead-free materials that could have the required properties that would enable it to be developed into a high temperature capacitor. NPL and SYF have each filed a Patent Application to protect a new high-K ceramic material (SBFT - Strontium-Bismuth-Ferrum-Titanate) with unprecedented energy storage performance up to 200 °C. The most innovative part of this material is that it can meet X7R and X8R characteristics in a totally different material chemistry, offering electrical properties that are not available in BaTiO3 based materials - such as low df and heat rise, low VC and high temperature stability).The objectives of the project and an update of status at the end of the project are as follows:a) Capacitor specifications for HF and HT switches: These issues were discussed with the Topic Manager and projects outputs defined. Two 4040 chip types of nominal 500V rated voltage and 1uF and 2.2uF capacitance value were specified.b) Improve capacitor performance and reliability above 125 °C: The material developed in the previous project has been optimised and improvement to component reliability has been demonstrated. This was mainly achieved by optimising dopant levels and processing conditions.c) Improve termination at high temperatures: This work has primarily been focussed on a plateable termination finish, but reliability results have been somewhat inconsistent using this finish, so an alternative material system which can be used for surface mount components but without a patented plateable finish has been evaluated with promising results.d) Cost-effective electrodes: Euro Support have worked on adjusting the basic material formulation to allow use of a lower sintering temperature. These changes have not yet been successfully implemented into MLCC's.e) Thick capacitors: This material system does not appear to suffer from issues relating to component thickness, so thick components have been made successfully.f) Energy density and breakdown field. This is lower than desired, but allowed manufacture of the specified components within the project timescales.At the end of the project, all deliverables have been met, but the project team are awaiting feedback on part performance from the Topic Manager.NPL are submitting an article on Lead-free ceramics with high energy density and reduced losses for high temperature applications to Advanced Engineered materials magazine.Syfer have submitted an article on MLCC's in automotive applications to Power Electronics EuropeSyfer have supplied parts to three interested customers (with NDA's) with a fourth NDA being prepared.Further work is on going on material and process optimisation with a view to qualification and release in 2018Project Context and Objectives:Automotive, aerospace, and energy production industries will greatly benefit from the development of semiconductor based electronics operating at temperature higher than 150 °C. Wide bandgap semiconductors like SiC and GaN are key enablers in such development as these allow electronics to function at much higher temperatures than silicon, and devices made from these materials will be able to handle more current and power compared to Si based ones. However, increasing operating temperatures compromise the performance and reliability of other components in the power electronic system, including capacitors and inductors, interconnects and packaging, and therefore complex cooling systems are required which adds complexity and volume to device design. This project directly addresses this issue which is the specific technological challenge of Call JTI-CS-2013-03-SGO-02-087 entitled “Technology development and fabrication of high-temperature high-frequency capacitors for power switch integration”, and proposes a thorough programme of work aimed at the development and fabrication of an optimized ceramic formulation which can provide highly reliable multilayer ceramic capacitors for power switch integration. This directly addresses the CfP by making ‘major advances in designing high performance lightweight and small volume power systems for avionic applications’ by making available high temperature capacitors (at least 150 ºC steady-state, with a view at achieving 200 ºC over the project duration) suitable for high frequency filtering and for embedment within solid-state power modules’. The project will additionally, ‘support other on-going activities targeting the demonstration of very compact converters by supporting the development of high performance high temperature ceramic (or equivalent performance) capacitors. This builds on a range of previous project within the Clean Sky Initiative.HITECA team members have previously investigated a range of lead-free materials that could have the required properties that would enable it to be developed into a high temperature capacitor. NPL and SYF have each filed a Patent Application to protect a new high-K ceramic material (SBFT - Strontium-Bismuth-Ferrum-Titanate) with unprecedented energy storage performance up to 200 °C, and fabricated MLCCs (see Figure 1), have shown unique properties. The most innovative part of this material is that it can meet X7R and X8R characteristics in a totally different material chemistry, offering electrical properties that are not available in BaTiO3 based materials - such as low df and heat rise, low VC and high temperature stability).The objective of the HITECA project is to make the following improvements relative to the current state of the art:a) Capacitor specifications for HF and HT switches: In close co-operation with the Topic Manager (TM), the temperature characteristics required for the capacitor need to be defined. For applications at temperatures above 150°C it needs to be discussed, if these products still need to have a temperature characteristic that is in accordance with the X9R specification, because this is referring to a capacitance variation between -55 and 200°C with respect to a room temperature reference value. It is an interesting question if a device that will operate at temperatures as high as 150°C due to the vicinity to active components, needs to be referenced to room temperature. Capacitors will have to operate at frequencies between 400 kHz and up to 4MHz. The exact frequencies and amplitudes depend on the specifics of the capacitor topology and the Topic Manager will provide a specification for this when the project starts.b) Improve capacitor performance and reliability above 125 °C: The temperature range of the material’s performance and reliability will be extended. This means that the ceramic capacitor which can currently reliably operate at 125°C needs to be further developed to offer comparable performance at 150°C and later to 200°C. However, the sources of electrical failure in SBFT ceramic capacitors are not well understood. These may come from the SBFT ceramic (e.g. space charges, oxygen vacancies) or from the MLCC design (e.g. electrode metal migration to the ceramic layer). c) Improve termination at high temperatures: Ensuring that the termination finish is compatible with the upper temperature rating is also a major priority in this project. As the upper rated temperature is increased there are extra stresses formed between the end termination and ceramic body of the chip. The termination material (a silver precious metal layer) must therefore be optimised as the base ceramic material is developed to ensure that reliability performance is maintained. d) Cost-effective electrodes: An additional focus will be laid on the lowering of the firing temperature of the SBFT ceramic. This would allow the use of a higher Ag content in the inner electrodes which are now used with 30% of the expensive metal Pd. A reduction of the Pd level to 10% without any performance loss will be targeted in the material development as well. e) Thick capacitors: In order to supply the high capacitance values that are likely to be required with this material, large, thick components are likely to be most common. In standard multilayer ceramic capacitors larger, thicker parts suffer from voltage related stress cracking which impacts the maximum capacitance values. This aspect will be investigated during the project.f) Energy density and breakdown field: High energy density at the operated voltage is required to reduce the volume of stacked capacitors to deliver the required capacitance. Energy density is a useful metric as it accounts for the nonlinear electric field dependence of polarization. For the new capacitors an energy density of > 1 J/cm3 will be aimed, which could be achieved by optimizing breakdown field to above 100 kV/cm.Project Results:WP 1 D1.1 Technology Review Report completed in February 2015. This report:a) Reviewed capacitors currently available for high-frequency and high-temperature switches for avionic applications.b) Benchmarked ceramic capacitors currently available from other suppliers.c) Investigated physical and electrical mechanisms of ceramic oxides and multilayer ceramic capacitor (MLCC) degradation.d) Detailed measurement and characterisation techniques to be used within the project.D1.1 provided the background material required to successfully engineer a device sufficiently reliable for commercial development from a new material.2.2 WP1 D2.1 Technology Roadmapping HITECA specification and range proposal was completed in February 2015. This report: a) Reviewed the circuit requirements for the test part. b) Introduced the prototype Inverter. c) Road mapped the requirements of the Topic Manager. d) Introduced HITECA range proposals. e) Recommended test components to be manufactured for WP3 and WP4, together with expected performance over a range of temperatures and voltages.2.3 WP2. Sample and product development. This work package forms the main body of the research and development work for this project. First period:-a) Formulation development. Ceramic powder formulation trials are carried out at Euro Support, producing ceramic discs which are characterised at Euro Support, with additional testing being carried out at NPL as necessary. Promising formulations are then submitted to Knowles UK for capacitor trials.So far 8 bulk samples from Euro Support have been evaluated at Knowles, with many more intermediate (blended) samples also evaluated as MLCC’s. Mn and X7R doping levels have been found to be important to the formulation, but so far no material has outperformed the original ‘reference’ material. Recent understanding of the lattice structure of the material has led to recent promising disc results and further bulk samples are in manufacture.b) Process optimisation – termination etc.Knowles have spent much time investigating the process variables of the HITECA ‘reference’ formulation, with a view to optimising processing conditions for this material system in parallel to the formulation work. This work has highlighted the importance of ceramic sintering temperature and termination type and coverage in achieving reliable parts. This work is ongoing.Second period a) Formulation development. Ceramic powder formulation trials are carried out at Euro Support, producing ceramic discs which are characterised at Euro Support, with additional testing being carried out at NPL as necessary. Promising formulations have been submitted to Knowles UK for capacitor trials.A further 9 bulk samples from Euro Support have been evaluated at Knowles during period 2, with many more intermediate (blended) samples also evaluated as MLCC’s. Mn and X7R doping levels have been optimised, but no other modifications to the formulation have been identified as beneficial. b) Process optimisation – termination etc.Knowles have continued to spend time investigating the process variables of the HITECA ‘reference’ formulation, with a view to optimising processing conditions for this material system in parallel to the formulation work. This work has been affected by the inability to determine a fully compatible termination for a plated finish, but an alternative, non plated termination is offering what looks to be, on initial results, a very promising alternative surface mount finish. Work will continue outside this project to complete this optimisation work using the ceramic formulation identified during the project.2.4 WP3. MLCC manufacture not optimised.The parts as defined in WP1 were manufactured and tested using the ‘reference’ material and optimised processing conditions. Parts meeting the output targets for the project have been submitted to the topic manager as D3.1 and D3.2. At the time of writing this report there has been no feedback on the test samples.WP4. MLCC manufacture optimised.The parts as defined in WP1 were manufactured and tested using the optimised reference material and optimised processing conditions. Parts meeting the output targets for the project have been submitted to the topic manager as D4.1 and D4.2. At the time of writing this report there has been no feedback on the test samplesPotential Impact:The project addressed the two core objectives of the CfP:• make major advances in designing high performance lightweight and small volume power systems for avionic applications’ by making available high temperature capacitors (at least 150 ºC steady-state, with a view at achieving 200 ºC over the project duration) suitable for high frequency filtering and for embedment within solid-state power modules, and thereby,• support other on-going activities targeting the demonstration of very compact converters by supporting the development of high performance high temperature ceramic (or equivalent performance) capacitorsImpactsThis project addressed a work task within the SGO (Systems for Green Operation) ITD, and in particular Workpackage 2, Management of Aircraft Energy (MAE) and specifically WP2.3 Technologies Adaptation. The MAE Workpackage as a whole covers the development of new architectures and technologies for power generation, distribution, conversion and storage. This includes improvement/development of the individual new electrical systems with higher power/weight ratio as well as the implementation of electrical energy management functions will be developed and thermal management.Expected impacts of SGO activities as a whole are expected to be 5-9% CO2 reductions on a typical mission through system level improvements in components and their efficiency and weight reduction, with aircraft efficiency savings as a whole contributing 20-25% of the targeted reductions of 50% in CO2 emissions/passenger kilometres set by the Advisory Council for Aeronautical Research in Europe to be attained between 2000 and 2020. (While individually small, the size of the contribution possible makes improvements in technologies such as these vital, with air transport's contribution to climate change representing 2% of human-induced CO2 emissions (and 12% of all transport sources) with flights producing 628,000,000 tonnes of CO2 yearly). With an estimated doubling of the commercial aircraft fleet being estimated to be required by 2050 internationally and a 4-5% increase per annum in air travel demand over the next 20 years, the increased contribution, and indeed the increased scope for saving, in the air industry is vast, with the industry already moving over 2.2 billion passengers annually, generating 32 million jobs globally and having a nett economic impact estimated at US$ 3.56 billion. The HITECA project addressed these impacts by:a) Enhancing European competitiveness in the field of high power density high efficiency power system development,b) Establishing a supply chain for high performance high temperature, high frequency capacitors with avionic/aerospace qualification, and,c) Developing new knowledge and understanding as well as developed technology that will impact many other sectors, these include for example: • Smoothing of renewable energy sources and fuel cells. • Pulse power applications. Applications which require sporadic, rapid high energy discharges, eg. Defibrillators, Camera Flashes, Neurological Stimulators.• Standby Power Sources: Medical PC power supply backup.• Boost Applications: Electric forklift truck: Drives around on standard battery power but when lifting the extra power boost is provided by capacitor.• Power Supplies: Current solution for smoothing is to use a combination of high capacitance electrolytic capacitors and multi-layer ceramic capacitors (MLCC) to provide smoothing and high frequency filtering, advancements in the capabilities of MLCC could allow them to entirely replace the electrolytic and enable more reliable power supply design.• LED lighting, which is a large and rapidly expanding market set to be worth $42bn by 20192. (2http://www.lighting.co.uk/news/latest-news/global-led-market-to-be-worth-42bn-by-2019/8655203.article).Dissemination and/or exploitation of project results, and management of intellectual propertySYF have invested in this technology and subject to product launch, will be able to exploit innovations via their market presence in automotive, defence, and electronics industries. Typical applications within aerospace will include dc and ac power supplies where capacitor temperature and voltage stability are beneficial. It is also envisaged that the HITECA material could potentially replace multi-chip stacked capacitors and other less stable capacitors, with smaller components. SYF currently has a very small market share, probably <1%, and the total potential market could run into 10’s of millions of euro. Based on data from May 2009, SYF sales output is currently 7% for automotive market and 9% for power supply products. SYF estimated market share is currently <0.05% for both the automotive and power supply product. This would estimate each of these markets to be approximately £250 million as they stand currently, with significant potential for expansionNPL will also exploit the project output through developing intellectual property relating to the metrology of energy storage in materials. ESAM will initially serve SYF with materials for the development of the markets described above. Once the technology is successfully introduced in the market, ESAM will negotiate with SYF and NPL (IP holders of the IP existing Background), under which conditions ESAM would be allowed to sell the product to additional customers. Scientific knowledge will also be disseminated, and wider applications sought through knowledge transfer networks, the Piezo Institute, and conferences (on the premise that any IP is properly protected prior to publication).The principles of intellectual property management described in the model collaboration agreement have been adopted in this project. At he end of the project, there has been no additional IP generated to supplement the previously issued patent.The project partners have published and are publishing relevant information as it becomes available for release.:NPL have submitted Lead-free ceramics with high energy density and reduced losses for high temperature applicationsBy T. M. Correia, M Stewart*, A. Ellmore, and K. Albertsento Advanced Engineered materials magazineSyfer have submitted an article on MLCC's in automotive applications to Power Electronics EuropeSyfer have supplied parts to three interested customers (with NDA's) with a fourth NDA being prepared.Syfer mentioned the HITECA material and its potential benefits at an Electronica press presentation in 2016 and will continue to present the material benefits to customers during 2017.Ethical IssuesIt should be noted that this parts manufactured from HITECA material could be subject to dual use and potential terrorist abuse. While immediate use is not foreseen or expected it should be stated that any system and component that can be used for the improvement of civil avionics, can obviously be used just as easily in military aircraft. Lastly, project output could in theory be used in terrorist applications such as detonators however immediate usage of output to this end is most unlikely as many alternatives already exist. Any such future part would be covered and licenced by dual use restrictions.Several ISO (and other standards) are already in place which control and mitigate any production and work and environment issues that may occur and these include:• ISO 14001:2004, held by SYF, allowing the adoption of an effective environmental management system for; reduced cost of waste management; Savings in consumption of energy and materials and; compliance with prevalent environmental laws and regulations.• BS OHSAS 18001 (Occupational Health and Safety), held by SYF, which “sets out the minimum requirements for occupational health and safety management best practice” and allows for the creation of: the best possible working conditions; identification of hazards and controls to manage them; reducing workplace accidents and illness. • ESAM is currently working to an environmental management system according to the Dutch “Besluit Risico’s Zware Ongevallen 1999”. Consideration of gender aspectsThe Consortium is committed to the promotion of gender equality and a range of effective policies are already in place, this is clearly demonstrated through the fact that 3 of the 6 named individuals that have worked on the project are female. Such a ratio may be considered unusual in science and engineering where there has been a traditional male bias. List of Websites:Not applicable
