Article
Engineering, Electrical & Electronic
Mohsin Asad, Amit Kumar Singha, Ravada Madhu Sudhan Rao
Summary: This article proposes simple models for dead time optimization in a GaN-based buck converter under different load conditions, and validates these models with a buck converter prototype.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Jingcun Liu, Ruizhe Zhang, Ming Xiao, Subhash Pidaparthi, Hao Cui, Andrew Edwards, Lek Baubutr, Cliff Drowley, Yuhao Zhang
Summary: This letter presents the avalanche and surge current ruggedness of the industry's first 1.2-kV-class vertical GaN p-n diodes on 100-mm GaN substrates. The diodes exhibit a critical avalanche energy density and surge energy density, as well as small reverse recovery and fast switching capabilities, highlighting the high ruggedness of GaN p-n junctions.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Philipp Gribisch, Rosalia Delgado Carrascon, Vanya Darakchieva, Erik Lind
Summary: In this work, quasi-vertical gallium nitride (GaN) fin field effect transistors (FinFETs) on silicon carbide (SiC) substrates and the influence of a postgate metallization annealing (PMA) were fabricated and investigated. The devices showed low subthreshold swings (SSs) of around 70 mV/dec. They also exhibited low ON-resistance, high breakdown voltage, and reduced gate leakage current when subjected to PMA. The effective and field-effect mobility of the fin channel was comparable to similar devices reported previously.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Wei Lin, Maojun Wang, Ruiyuan Yin, Jin Wei, Cheng P. Wen, Bing Xie, Yilong Hao, Bo Shen
Summary: The breakdown voltage of vertical GaN p-n diode is successfully boosted from 661V to 1489V using the HMSG-JTE technique, improving the electric field distribution and enhancing device performance.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Engineering, Electrical & Electronic
M. Florovic, J. Kovac, A. Chvala, J. -c. Jacquet, S. L. Delage
Summary: In this article, pinch-off voltage biasing was used for the first time to determine the average channel temperature of the AlGaN/GaN HEMT, excluding the device's electrical parameters dependence in the linear operating mode. The theoretical part focused on the thermal model with temperature-dependent thermal resistance to determine the average temperature of the HEMT under quasi-static operation. The experimental part discussed the appropriate methods for determining the active area average temperature using constant isothermal saturation current or short-pulse current.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Ruizhe Zhang, Jingcun Liu, Qiang Li, Subhash Pidaparthi, Andrew Edwards, Cliff Drowley, Yuhao Zhang
Summary: Insufficient short-circuit robustness of currently commercial GaN power devices is a major obstacle for their applications in automotive powertrains. This paper presents a breakthrough in short-circuit capability through a vertical GaN fin-channel junction-gate field-effect transistor (Fin-JFET). The Fin-JFET shows excellent short-circuit resistance and retains stability even after failure, making it highly desirable for power electronics systems.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Ming Xiao, Yifan Wang, Ruizhe Zhang, Qihao Song, Matthew Porter, Eric Carlson, Kai Cheng, Khai Ngo, Yuhao Zhang
Summary: This study presents a novel junction termination extension (JTE) technique with a graded charge profile for vertical GaN p-n diodes. The fabrication process does not require GaN etching and only involves a single-step implantation. The fabricated GaN p-n diodes exhibit high breakdown voltage and robust avalanche current density, making them suitable for various vertical GaN devices.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Tiangui Hu, Lixia Zhao, Yujing Wang, Hailong Lin, Shihong Xie, Yin Hu, Chang Liu, Wenkai Zhu, Zhongming Wei, Jian Liu, Kaiyou Wang
Summary: This study demonstrates a high-sensitivity and fast-speed UV photodetector based on asymmetric Au/nanoporous-GaN/graphene vertical junctions. The nanoporous GaN-based vertical photodetector shows excellent rectification ratio, high photo-responsivity, and specific detectivity, as well as fast rise/decay time.
Article
Engineering, Electrical & Electronic
Geon Uk Kim, Young Jun Yoon, Jae Hwa Seo, Min Su Cho, Sang Ho Lee, Jin Park, Hee Dae An, So Ra Min, In Man Kang
Summary: This paper presents the design and analysis of GaN-based vertical trench MOSFETs using 3-D TCAD simulation, revealing that cylindrical devices perform inferiorly to hexagonal devices in terms of crystal directions. The simulation results offer insights and design guidelines on how the electrical properties of trench FETs are affected by cross-section shape.
JOURNAL OF SEMICONDUCTOR TECHNOLOGY AND SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Can Zou, Zixuan Zhao, Mingjun Xu, Xingfu Wang, Qing Liu, Kai Chen, Longfei He, Fangliang Gao, Shuti Li
Summary: To address the issue of minority carrier storage time in bipolar transistors, a hot electron transistor (HET) has been proposed. This device offers high working speed and the ability to perform complex logic functions with just one component. A mixed-dimensional HET composed of GaN/AlN microwires, graphene (Gr), and Si has been demonstrated, which achieves high speed hot electrons by injecting electrons between GaN/AlN into graphene through F-N tunneling mechanism, allowing for ballistic transport and collection through low-barrier Si. The device exhibits a record DC gain of 16.2, collection efficiency close to the limit of 99.9% based on GHET, emitter current density of 68.7 A/cm2, high on/off current ratio of approximately 107, and wide current saturation range, making it suitable for potential applications as a power amplifier.
Article
Engineering, Electrical & Electronic
Mohammad Sajid Nazir, Pragya Kushwaha, Ahtisham Pampori, Sheikh Aamir Ahsan, Yogesh Singh Chauhan
Summary: In this work, a phenomenological cryogenic model for GaN HEMTs is proposed and validated with experimental characterization results. The model accurately captures the negative threshold voltage shifts and kink effects observed at cryogenic temperatures. The impact of temperature, impact ionization, and field-dependent trapping/detrapping on performance is explored and implemented in the model to explain these phenomena.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Jingcun Liu, Ruizhe Zhang, Ming Xiao, Subhash Pidaparthi, Hao Cui, Andrew Edwards, Cliff Drowley, Yuhao Zhang
Summary: This article demonstrates for the first time that avalanche current in GaN JFETs can flow through the source by using a MOSFET driver with a large gate resistance or an RC-interface driver. Physics-based mixed-mode electrothermal simulations reveal the carrier dynamics under different avalanche paths. Additionally, it shows that the RC-interface driver outperforms the MOSFET driver for GaN JFETs.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Automation & Control Systems
Xiao Long, Zhao Jun, Botao Zhang, Dongdong Chen, Wu Liang
Summary: This article presents a unified electrothermal behavior modeling method for SiC MOSFET and GaN HEMT, with a parameter extraction method based on modeling data and optimization algorithm. The proposed modeling method has been verified through simulation and experiment, showing its correctness and applicability to several commercially available devices.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Binxing Li, Gaolin Wang, Shaobo Liu, Nannan Zhao, Guoqiang Zhang, Xueguang Zhang, Dianguo Xu
Summary: This article proposes an analytical model for crosstalk voltage in GaN HEMT, taking into account nonlinearities in junction capacitance and reducing the number of model parameters with an equivalent circuit approach. The model's accuracy is verified and extensive investigation into the impact of device and circuit parameters on crosstalk phenomenon is conducted. The proposed model, validated through simulations and experiments, can guide device selection and PCB circuit design.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Bikramjit Chatterjee, Dong Ji, Anchal Agarwal, Silvia H. Chan, Srabanti Chowdhury, Sukwon Choi
Summary: In this study, an electro-thermal co-design analysis was conducted on vertical and quasi vertical GaN transistors, where the performance difference between vertical and quasi-vertical OG-FETs was discussed. The distribution of internal electric field and heat generation within OG-FETs was analyzed using electro-thermal device simulation. A 3D thermal model was utilized to assess the impact of design variables on the self-heating behavior of multi-cell arrays of OG-FETs.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Zhengliang Bian, Ke Zeng, Srabanti Chowdhury
Summary: A novel edge termination method has been reported for a 2.8 kV avalanche-capable vertical gallium nitride pn diode. By depositing a field plate on top of a hydrogen-plasma passivated p-type GaN layer, better electric field management was achieved to mitigate peak electric fields in the diode. Avalanche behavior was confirmed by the positive temperature coefficient of the breakdown voltage.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Kwang Jae Lee, Yusuke Nakazato, Jaeyi Chun, Xinyi Wen, Chuanzhe Meng, Rohith Soman, Maliha Noshin, Srabanti Chowdhury
Summary: This study presents experimental evidence for the use of nanoporous GaN (NP GaN) as a compensation layer to prevent the diffusion of magnesium (Mg) from p-type gallium nitride (p-GaN). Additionally, the study reveals the significant impact of NP GaN on the electron concentration of AlGaN/GaN structures.
Article
Engineering, Electrical & Electronic
Xinyu Zhou, Mohamadali Malakoutian, Rohith Soman, Zhengliang Bian, Rafael Perez Martinez, Srabanti Chowdhury
Summary: This article presents a modeling approach and implementation to study the impact of top-side diamond integration on the performance of a mm-wave GaN HEMT. The simulation results guide the optimization of RF performance and aid in the device design of diamond passivation.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Seungbin Jeong, Kwangjae Lee, Jaeyi Chun, Rohith Soman, Srabanti Chowdhury
Summary: GaN vertical FinFETs on a bulk GaN substrate were fabricated and their self-heating and DC-RF dispersion were investigated. The devices showed high drain current density and low gate leakage with low-temperature post-gate processes. The specific on-resistance was one of the lowest values reported, and low dispersion was observed for devices away from the wafer edge. The influence of self-heating was more significant as the fin width scaled down or the number of fingers increased.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Rafael Perez Martinez, David J. Munzer, Bhawani Shankar, Boris Murmann, Srabanti Chowdhury
Summary: There is a significant disconnect between the linearity metrics used by device and circuit engineers in GaN technology, which degrades its maximum performance. A detailed linearity analysis is conducted on four different GaN device variants using derivative superposition (DS) method to evaluate amplifier performance under modulated conditions. Conventional linearity metrics at the device level, such as output third-order intercept point (OIP3) and output 1-dB compression point (OP1 dB), are compared with communication standard-based metrics, including adjacent channel power ratio (ACPR) and error vector magnitude (EVM), to provide best practices for quantifying power amplifier (PA) linearity. The study reveals that employing more devices primarily improves the input-bias range of the device, not the peak amplifier performance under modulation. This work provides device engineers with a circuit-level perspective on linearity to enhance RF performance for practical deployment.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Editorial Material
Materials Science, Multidisciplinary
Grace Xing, Zetian Mi, Srabanti Chowdhury
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Crystallography
Xinyi Wen, Kwang Jae Lee, Yusuke Nakazato, Jaeyi Chun, Srabanti Chowdhury
Summary: For the first time, a low-temperature GaN (LT-GaN) layer prepared by MOCVD regrowth was used as a Mg stopping layer (MSL) for a GaN trench CAVET with p-GaN as a CBL. The MSL effectively suppresses Mg out-diffusion into the regrown AlGaN/GaN channel, enhancing the current capability of the GaN vertical devices. The study investigates the influence of MSL regrowth temperature and thickness on device performance and demonstrates that LT-GaN as the MSL is a promising approach for isolating Mg from subsequent layers in GaN vertical devices with a Mg-doped p-type layer.
Article
Physics, Applied
Maliha Noshin, Xinyi Wen, Rohith Soman, Xiaoqing Xu, Srabanti Chowdhury
Summary: In this study, N-polar AlGaN channel HEMT structures with varying Al mole fraction were grown using MOCVD. The high-quality morphology and Al composition of the structures were confirmed using atomic force microscopy and x-ray diffraction spectra. The results showed a decreasing trend in mobility with increasing Al mole fraction, which can be attributed to a combination of alloy-scattering and optical phonon-scattering mechanisms. HEMTs fabricated from these structures exhibited a drain current of 320 mA/mm for a 4 μm long-channel device.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Maliha Noshin, Rohith Soman, Srabanti Chowdhury
Summary: Devices made from ultrawide bandgap materials are being widely investigated for high-power and RF electronics. Nitrogen-polar GaN channel HEMTs exhibit better performance compared to their metal-polar counterparts. In this work, the first experimental demonstration of N-polar all-AlGaN HEMT devices with different Al compositions (20% and 30%) in the channel is reported. These devices showed high drive current, low leakage current, large on/off ratio, and high breakdown voltage without field plate structures.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Sudip K. Mazumder, Lars F. Voss, Karen M. Dowling, Adam Conway, David Hall, Robert J. Kaplar, Gregory W. Pickrell, Jack Flicker, Andrew T. Binder, Srabanti Chowdhury, Victor Veliadis, Fang Luo, Sameh Khalil, Thomas Aichinger, Sandeep R. Bahl, Matteo Meneghini, Alain B. Charles
Summary: This article provides an overview of power semiconductor devices (PSDs) for the distributed energy resource (DER) system. It begins with an introduction to electrically triggered silicon carbide (SiC) and gallium nitride (GaN) devices, followed by a brief explanation of ultrawide bandgap (UWBG) PSDs. Additionally, it discusses optically activated PSDs such as photoconductive semiconductor switches (PCSS) and optical bipolar PSDs, and concludes with an overview of PSD packaging and reliability considerations.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2023)
Proceedings Paper
Computer Science, Interdisciplinary Applications
Rafael Perez Martinez, Masaya Iwamoto, Jianjun Xu, Philipp Pahl, Srabanti Chowdhury
Summary: This paper compares the accuracy and attributes of different FET models in the context of GaN HEMT modeling. Three FET models implemented within PathWave Advanced Design System are compared, with a focus on analyzing the use of neural networks for modeling I-V and Q-V relations. The models are validated and benchmarked using data from a specific GaN-on-SiC HEMT, showing the power of neural network technology for accurately modeling thermal and trapping effects of GaN HEMTs.
2023 IEEE RADIO FREQUENCY INTEGRATED CIRCUITS SYMPOSIUM, RFIC
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Yuke Cao, James W. Pomeroy, Jingshan Wang, Patrick Fay, Bhawani Shankar, Srabanti Chowdhury, Martin Kuball
Summary: Semiconductor device developments are guided by simulations and comparing measured and simulated IV curves is a common method to assess device performance. However, the problem of low breakdown voltage due to different implantation or doping levels lacks guidance for mitigation. We present a technique based on EFISHG to directly measure electric strength in vertical GaN-on-GaN pn junctions with submicron resolution, which aids in improving device design and reducing product development cycles.
GALLIUM NITRIDE MATERIALS AND DEVICES XVIII
(2023)
Article
Materials Science, Multidisciplinary
Mohamadali Malakoutian, Rohith Soman, Kelly Woo, Srabanti Chowdhury
Summary: The increasing power demands of electronic applications, including 5G/6G, have made thermal management crucial. Enhancing heat transfer using thermally conductive materials like diamond is important to address the performance degradation and early failure caused by Joule heating in the device channel due to higher power. Diamond integration onto the device's top, near the channel, can be achieved through direct chemical vapor deposition.
Proceedings Paper
Computer Science, Artificial Intelligence
Dennis Rich, Anna Kasperovich, Mohamadali Malakoutian, Robert M. Radway, Shiho Hagiwara, Takahide Yoshikawa, Srabanti Chowdhury, Subhasish Mitra
2023 60TH ACM/IEEE DESIGN AUTOMATION CONFERENCE, DAC
(2023)
Proceedings Paper
Engineering, Multidisciplinary
Bhawani Shankar, Zhengliang Bian, Ke Zeng, Chuanzhe Meng, Rafael Perez Martinez, Srabanti Chowdhury, Brendan Gunning, Jack Flicker, Andrew Binder, Jeramy Ray Dickerson, Robert Kaplar
Summary: This study investigates the avalanche behavior and failure mechanism of 3 kV GaN-on-GaN vertical P-N diodes, aiming to identify issues with the device design and provide feedback for improvement based on the specific avalanche characteristics and failure mechanism.
2022 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM (IRPS)
(2022)
