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Sub KT low energy transistors and sensors

Exploitable results

With increasing miniaturization of semiconductor electronics an increasing fraction of the power to the circuit is converted into nondeterministic signals that add to the ambient noise. In commonly used device concepts noise degrades the performance. Interestingly, there are cases where noise, instead of degrading the device performances, can lead to enhanced signal to noise ratios, if principles of Stochastic Resonance (SR) are used. The partners of the present proposal undertake a coordinated effort including groups working on device theory, nanofabrication and device characterization to investigate the feasibility and potential of SR–nanoelectronic semiconductor devices. Using e.g. special FET like devices with tailored internal feedback the nonlinear dynamic transport properties in this regime will be explored for sensing and switching of sub thermal signals with the help of stochastic resonance-like dynamics. Within the proposal several key devices like ?residence time detectors and ?electrochemical capacitance feedback transistors will be realized and investigated for the first time. Concepts of integrated nanoscale circuits with efficient readout schemes, enhanced signal resolution in a noisy environment and stochastic resonance enhanced detection will be tested. By utilizing nonlinear transport in nanosystems the proposal has the potential to open a new window for electronic applications covering stochastic resonance phenomena, sub thermal switching and on chip noise control applications. It is the main objective of the SUBTLE project to evaluate the potential of nanoelectronic SR devices by physics and device modeling, nanodevice fabrication techniques as well as static and dynamic device characterization. The scientific approach of SUBTLE is based on the application of two effects in miniaturized electronics, which one usually tries to avoid in device design: back-action of the channel on the gate and noise induced switching. In order to make use of them and even to obtain signal gain, we will realize new types of transistors and circuits, which should allow exploiting noise enhanced switching by means of stochastic resonance phenomena (SR) and device intrinsic capacitance couplings associated with the electrochemical capacitance (EC) of low dimensional systems1. Recently proposed detection schemes will be applied in nanoelectronic semiconductor devices. In particular, three key properties will be addressed within the frame of the project: - Subthermal signal resolution - Noise activated switching - Noise enhanced signal processing The goal of the project includes the realization of three nanoelectronic key devices, which are based on SR and EC for enhanced switching in order to resolve sub thermal signals hidden by thermal noise if classical amplification schemes are applied: - Electrochemical capacitance induced feedback transistors (FBFETs) - Noise activated nonlinear devices (NADs) - Noise enhanced signal processing nodes (NESNs) These devices will be realized on the basis of high resolution nanofabrication and low dimensional, high mobility carrier systems aligned either vertically or laterally in GaAs and Si based semiconductor heterostructures Major achievements Major progress was made in all tasks according to our work plan. However, the following achievements should be highlighted: - Light-controlled morph gates and noise enhanced as well as noise induced universal logic gates as an artificial neuron node was realized (UWUERZ, UNIPG, VTT) - Submicron Resonant Tunneling diodes were implemented on light detection with a minimum detectability of a Signal-to-Noise Ratio (SNR) of just 0.001 (UWUERZ, UNIPG) - Demonstration of 150 MHz pattern generator (XENOS) - Demonstration of mesoscopic capacitors operating as an ideal detector with a Heisenberg efficiency of one (UNIGE) - We have investigated extensions of the fluctuation-dissipation theorem to non-equilibrium transport and derived relations (UNIGE) - Realization of magnetic-field asymmetry of nonlinear transport in narrow channels with asymmetric hybrid confinement (UWUERZ, UNIGE) - Device limits on noise-activated nonlinear detectors (NANDs) have been tested as electro-magnetic sensors. Within a nonlinear stochastic resonance process ultra small Signal-to-Noise Ratios (SNRs) have been detected. (UNIPG, UWUERZ) - Demonstration of coupled quantum dot FETs (LU) - Submicron Resonant Tunneling Diodes (RTDs) have been realized as universal and reconfigurable logic gates in a artificial neuron node (UWUERZ, UNIPG, VTT) - Demonstration of power gain in three-terminal junctions up to 1.5GHz. (UWUERZ) - Realization of memory diodes based on HfO2-InGaAs/InP (LU) - Demonstration and exploration on coupled electron and hole transport in a single 22 nm-thick double-gated Si quantum well (VTT) - Exploration on the bistable effect in electron-hole (EH) bilayer system as a function external gate biases, drive voltage and temperature (VTT) - Demonstration on three-terminal ballistic junctions on silicon on insulator wafers (LU) Plan for use and dissemination of the knowledge In the third year, main efforts of the project were dedicated to optimize the devices and structures, developed in the framework of SUBTLE during year 1 and 2. The main focus hereby was to put on their relevance for possible future applications. Also the modeling of the internal physical processes was a field of intense efforts. In both strategic directions, experimental work and basic theoretical understanding, the state of the art was pushed significantly forwards. Therefore, the knowledge management was obliged to find a balance between the protection of intellectual property and dissemination of results via publication in journals, conference presentations, PhD thesis and other public domain routes. - Exploitation activities For the commercial exploitation of the new high speed SUBTLE pattern controller, first contacts have been initiated. Especially tool supplier for applications that need to process large exposure areas show interest in a high speed direct write tool. Meetings with possible customers have already taken place (but may not be further disclosed here due to NDA bindings). As well, solutions for high speed electron optic columns have been investigated. Here, especially columns with electrostatic deflection systems are suitable to support the high writing speed of the new pattern controller. Contacts to 3 companies have been initiated or expanded: Hitachi High Technology HHT, A&D and Novelx. Based on the patent of the SUBTLE sensor (WO/2009/106595), already different industrial partners were contact for exploitation of different applications.