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[IEEE 2018 IEEE International Meeting for Future of Electron Devices, Kansai (IMFEDK) - Kyoto, Japan (2018.6.21-2018.6.22)] 2018 IEEE International Meeting for Future of Electron Devices, Kansai (IMFEDK) - Improved Current Collapse in AlGaN/GaN MOS-HEMTs with Dual Field-Plates
摘要： We fabricated AlGaN/GaN MOS-HEMTs with a dual-field-plate (FP), composed of gate-FP and source-FP. Using pulsed I-V technique, the effect of FP on current collapse was studied. Applying a high positive gate voltage resulted in current collapse suppression. It was found that the use of dual-FP was effective to significantly suppress the current collapse.
关键词： current collapse,MOS,AlGaN/GaN,field-plate
更新于2025-09-23 15:22:29
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MPA-GSH functionalized AlGaN/ GaN High Electron Mobility Transistor based sensor for Cadmium ion detection
摘要： This work demonstrates a novel AlGaN/GaN high electron mobility transistor (HEMT) based cadmium ion (Cd2+) sensor with Mercaptopropionic Acid (MPA) and Glutathione (GSH) functionalization. The sensing response of the sensor was analysed by detecting Cd2+ ions at different concentrations. The AlGaN/GaN HEMT sensor exhibits excellent response with the sensitivity of 0.241 μA/ppb, a fast response time of ~ 3 seconds and a lower detection limit of 0.255 ppb. The observed lower detection limit is significantly lower than the World Health Organization (WHO) standard recommended limit for Cd2+ ions in drinking water. Furthermore, the sensor showed good selectivity of Cd2+ ions towards other heavy metal ions. The results indicate that the binding properties of GSH to Cd and the sensitivity of 2-D electron gas (2DEG) towards the variation of charges at the gate region makes the device highly sensitive with rapid detection of Cd2+ ions.
关键词： MPA,Cd2+ ions,AlGaN/GaN HEMT,sensing,GSH
更新于2025-09-23 15:22:29
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Task-Oriented GAN for PolSAR Image Classification and Clustering
摘要： Based on a generative adversarial network (GAN), a novel version named Task-Oriented GAN is proposed to tackle difficulties in PolSAR image interpretation, including PolSAR data analysis and small sample problem. Besides two typical parts in GAN, i.e., generator (G-Net) and discriminator (D-Net), there is a third part named TaskNet (T-Net) in the Task-Oriented GAN, where T-Net is employed to accomplish a certain task. Two tasks, PolSAR image classification and clustering, are studied in this paper, where T-Net acts as a Classifier and a Clusterer, respectively. The learning procedure of Task-Oriented GAN consists of two main stages. In the first stage, G-Net and D-Net vie with each other like that in a general GAN; in the second stage, G-Net is adjusted and oriented by T-Net so that more samples, which are benefit for the task and called fake data, are generated. As a result, Task-Oriented GAN not only has the advantage of GAN (no-assumption data modeling) but also overcomes the disadvantage of GAN (task-free). After learning, fake data are employed to enrich training set and avoid overfitting; so Task-Oriented GAN performs well even if the manual-labeled data are small. To verify the effectiveness of T-Net, a visualized comparison is provided, where some fake digits generated from Task-Oriented GAN are illustrated along with that from GAN. What is more, considering that there is a great difference between PolSAR data and general data, in our PolSAR image classification and clustering tasks, the specific PolSAR information is inserted into the structure of the Task-Oriented GAN. This enables researchers to mine inherent information in PolSAR data without any data hypothesis and find ways for small sample problem at the same time. Experiment results tested on three PolSAR images show that the proposed method performs well in dealing with PolSAR image classification and clustering.
关键词： generative adversarial network (GAN),task-oriented,Clustering,PolSAR image classification
更新于2025-09-23 15:22:29
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Experimental Evaluation and Analysis of Switching Transient's Effect on Dynamic On-Resistance in GaN HEMTs
摘要： The dynamic on-resistance is problematic as it can impair the converter's efficiency due to the increased conduction loss. In this paper, the hard-switching transient's effect on the dynamic on-resistance is, for the first time, evaluated experimentally on a commercial high-voltage GaN HEMT. A new R_dyn-ds,on measurement circuit with fast sensing speed is designed, and an accurate measurement of R_dyn-ds,on can be realized experimentally within 49.6 ns after the device's current reaches to the load current. A double-pulse-test setup is designed to comprehensively evaluate the switching transient's effect on R_dyn-ds,on under different operating conditions. From the experimental results, it is found that the turn-on and turn-off gate resistance have a significant impact on the dynamic on-resistance whereas the cross-talk effect on R_dyn-ds,on is negligible. Specifically, at 400 V/25 A, more than 27% (28.2%) increase in R_dyn-ds,on is observed when the external turn-on (turn-off) gate resistance increases from 0 Ω to 20 Ω. Detailed discussion and quantitative analysis are provided to explain the experimental results. In terms of the turn-on process, it is concluded that the R_dyn-ds,on variation is mainly caused by the different numbers of generated hot electrons. For the turn-off transient, it is confirmed the variation of drain current at different dv/dt slew rate leads to the R_dyn-ds,on difference.
关键词： switching transients,Dynamic on-resistance,GaN HEMTs,hot electrons
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - A GaN/Si Hybrid T-Type Three-Level Configuration for Electric Vehicle Traction Inverter
摘要： The inverter partial load performance is extremely important for the weighted average efficiency and vehicle mileage as during 95% of the driving time, the traction inverter for an electric vehicle is operating under < 30% full load. A GaN/Si hybrid T-Type Three-level configuration is proposed to enhance the light load efficiency. Due to the zero-reverse recovery of GaN HEMTs and the halved voltage stress across the device, the switching energy of IGBT is significantly reduced. The GaN neutral clamping leg will be disabled at full load to avoid employing full current-rating GaN HEMTs for BOM cost reduction. A GaN/Si hybrid T-type three-level phase-leg is prototyped to validate the design concept. Compared with conventional two-level configuration, the switching-on loss of IGBT in hybrid T-type configuration is reduced by about 92%, and the switching-off loss is reduced by about 83% in the whole operating range. The system weighted-average efficiency analysis for a 150kW, 800V traction inverter is also presented.
关键词： Three-level inverter,GaN HEMT,Traction Inverter
更新于2025-09-23 15:22:29
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Donor Impurity States in Semiconductor Zincblende Nitride Quantum Systems as a Source of Nonlinear Optical Response
摘要： The optical absorption and the optical rectification coefficients associated to hydrogenic impurity interstate transitions in zincblende GaN-based nanostructures of the quantum wire type are investigated. The system is assumed to have cylindrical shape and the influence of external tuning probes such as hydrostatic pressure and static electric fields is particularly taken into account. The electron states are obtained within the effective mass approximation, via the exact diagonalization of the donor-impurity Hamiltonian with parabolic confinement. The nonlinear optical coefficients are calculated using a nonperturbative solution of the density-matrix Bloch equation. Our results show that the resonance-related features of the optical response become shifted in the frequency range of the incident radiation due to the effect of the hydrostatic pressure, the strength of the applied field and the change in the impurity center position.
关键词： Quantum Wire,Nonlinear Optics,Hydrostatic Pressure,Zincblende GaN
更新于2025-09-23 15:22:29
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The Temperature Dependences of the Electron-Piezoelectric Potential Phonon Interacting System of Quasi Two Dimensional System in GaN and ZnS
摘要： We investigated theoretically the temperature dependence of the quantum optical transition of quasi 2-Dimensional Landau splitting system, in GaN and ZnS. We apply the Quantum Transport theory (QTR) to the system in the con?nement of electrons by square well con?nement potential. We use the projected Liouville equation method with Equilibrium Average Projection Scheme (EAPS). Through the analysis of this work, we found the increasing properties of Quantum Transition Line Shapes (QTLSs) and the Quantum Transition Line Widths (QTLWs) of CdS and GaN with the temperature we also found that QTLW, (cid:2)(cid:3)T (cid:4) of ZnS < (cid:2)(cid:3)T (cid:4) of GaN in (cid:5) = 394 (cid:6)m.
关键词： Quantum Transport Theory,Quantum Transition Line Widths (QTLW),Quantum Transition Line Shapes (QTLS),GaN and ZnS,Cyclotron Resonance,Equilibrium Average Projection Scheme (EAPS),Electron Phonon Coupling System
更新于2025-09-23 15:22:29
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3D GaN Fins as a Versatile Platform for a-Plane-Based Devices
摘要： GaN fins on GaN-on-sapphire templates are fabricated by continuous mode selective area metalorganic vapor phase epitaxy. The fins exhibit high aspect ratios and smooth nonpolar a-plane sidewalls with an ultra-low threading dislocation density of a few 105 cm?2 making them ideally suited for optoelectronic to electronic applications. A detailed analysis of the inner structure of GaN fins is provided by the help of marker layer experiments and correlation of results from fins fabricated under different growth conditions, leading to the development of a growth model to explain the final geometry and optical as well as electrical properties of these high aspect ratio fins. Distinctly different material properties for the central and outer parts of the fins are detected. Whereas the outer sidewalls represent high quality GaN surfaces with very low defect densities, a strong quenching of near band edge emission (NBE) in the central part of the fins is accompanied by heavy compensation of free electrons. A possible explanation is the incorporation of excessive point defects, like intrinsic defects or carbon impurity. The sidewall regions, however, prove to be highly suitable for device applications due to their strong NBE emission, low dislocation density, and high free carrier concentration.
关键词： marker layers,threading dislocation density,GaN fins,selective-area MOVPE,a-plane sidewalls
更新于2025-09-23 15:22:29
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A novel GaN-based lateral SBD with a TUG-AlGaN/GaN heterojunction
摘要： In this study, a novel GaN-based lateral Schottky barrier diode (SBD) with a thin upward graded AlGaN (TUG-AlGaN) barrier layer is proposed and investigated. The TUG-AlGaN layer upward graded from 0 to 0.50 mole fraction is used to replace the thick AlGaN layer of the heterojunction, which can reduce the distance from the 2-D electron gas (2DEG) to the Anode electrode, retain high density of 2DEG near the heterojunction, and eliminate the abrupt AlGaN/GaN conduction band offset at same time, subsequently can reduce the turn-on voltage and on-state voltage. The simulated results show that compared with the conventional SBD (with 25 nm Al0.23Ga0.77N layer), the proposed SBD achieves 0.32V reduction in turn-on voltage, and 1.21V reduction in on-state voltage. Meanwhile, although the proposed SBD doesn’t deliver obvious improvement in static characteristics when compared with the GaN-Based lateral field-effect rectifier (L-FER) (with 25 nm Al0.23Ga0.77N layer), the reverse recovery time of the proposed SBD is much smaller than that of the L-FER (with 25 nm Al0.23Ga0.77N layer). The outstanding static characteristics combined with excellent switching characteristics reveal its great potential for future power applications.
关键词： turn-on voltage,switching characteristics,thin upward graded AlGaN barrier layer,GaN-based lateral Schottky barrier diode
更新于2025-09-23 15:22:29
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Selective Area Deposition of Hot Filament CVD Diamond on 100 mm MOCVD Grown AlGaN/GaN Wafers
摘要： A new technique is reported for selective growth of polycrystalline diamond by hot filament chemical vapor deposition (HFCVD) on AlGaN/GaN-on-Si (111) wafers without degradation of the underlying layers. Selective diamond seeding is accomplished by dispersing nano-diamond seeds in photoresist and patterned lithographically prior to HFCVD growth. A thin layer of plasma enhanced CVD SiNx, deposited prior to seeding and diamond deposition, was found to be essential to protect the AlGaN/GaN wafer. Methane concentration of 3.0% was used to achieve increased diamond growth rate and faster surface coverage. Excellent selectivity and minimal AlGaN surface damage were achieved due to the protective layer and faster surface coverage with increased methane concentration. Damage mitigation was confirmed by comparison of atomic force microscopy, x-ray diffraction, and Raman spectroscopy, each conducted before and after diamond deposition, and by SEM images of the final structures.
关键词： 2DEG,Reciprocal space mapping,III-Nitride,SiNx,Selective area deposition,CVD diamond,Photolithography,GaN decomposition
更新于2025-09-23 15:22:29