Article
Engineering, Electrical & Electronic
Xiaolu Guo, Yaozong Zhong, Yu Zhou, Xin Chen, Shumeng Yan, Jianxun Liu, Xiujian Sun, Qian Sun, Hui Yang
Summary: This work presents a 1200-V quasi-vertical GaN-on-Si p-n diode with a 6.6-μm thick high-quality GaN drift layer, which exhibits excellent static and dynamic performance. The diode shows stable operation at high temperatures and can effectively recover after power cycling tests. The experimental results indicate a reduced dependence of the dynamic on-resistance on the off-state voltage.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Xuan Liu, Maojun Wang, Jin Wei, Cheng P. Wen, Bing Xie, Yilong Hao, Xuelin Yang, Bo Shen
Summary: Utilizing hydrogen plasma treatment and controlled diffusion, a junction termination extension (JTE) structure with gradient hole density (GHD) is spontaneously formed for vertical gallium nitride (GaN) p-n diode based on selective area partial passivation of Mg acceptors with hydrogen. The reverse bias for the quasi-vertical GaN-on-Si p-n diodes to reach a leakage current of 1 A/cm(2) was boosted from 631 to 1100 V. Additionally, the fabricated diode exhibited superior rectifying behavior with an ON/OFF-current ratio of 10(12) and a specific differential ON-resistance of 0.75 m omega middot cm(2).
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Materials Science, Multidisciplinary
Vishank Talesara, Yuxuan Zhang, Zhaoying Chen, Hongping Zhao, Wu Lu
Summary: In this study, vertical GaN p-n diodes grown on hydride vapor epitaxy substrates by metal organic chemical vapor deposition are reported to exhibit excellent performance. This can be attributed to the high epitaxial material quality and optimized low anode contact resistance.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Nilushi Wijeyasinghe, Olga Solomeshch, Nir Tessler, Dimitra G. Georgiadou, Thomas D. Anthopoulos
Summary: This study reports on CuSCN Schottky diodes that are processed from solution with nanogap electrodes and doped with C60F48 to improve their operating characteristics. The doped diodes exhibit enhanced performance and are suitable for flexible circuits and IoT devices.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Electrical & Electronic
Prakash Pandey, Tolen M. Nelson, William M. Collings, Michael R. Hontz, Daniel G. Georgiev, Andrew D. Koehler, Travis J. Anderson, James C. Gallagher, Geoffrey M. Foster, Alan Jacobs, Mona A. Ebrish, Brendan P. Gunning, Robert J. Kaplar, Karl D. Hobart, Raghav Khanna
Summary: A simple edge termination structure for a GaN p-n diode is proposed, which has been empirically validated to increase breakdown capability. This technique reduces complexity in manufacturing and improves the device's voltage-blocking ability.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Physics, Applied
Kai Fu, Ziyi He, Chen Yang, Jingan Zhou, Houqiang Fu, Yuji Zhao
Summary: This study proposes the use of hydrogen plasma treatment to solve the premature breakdown issue in GaN power devices and demonstrates their avalanche capability. The results show that under appropriate process conditions, vertical GaN power devices can achieve avalanche capability. This is an important reference for the future development of efficient and robust GaN power electronics.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Yu Duan, Jingshan Wang, Zhongtao Zhu, Guanxi Piao, Kazutada Ikenaga, Hiroki Tokunaga, Shuuichi Koseki, Mayank Bulsara, Patrick Fay
Summary: We present a ion-implanted triple-zone junction termination extension (JTE) for vertical GaN p-n diodes. The design of triple-zone JTE reduces the peak electric fields at the contact metal edge and at the edge of the JTE compared to conventional approaches. Experimental results show that GaN p-n diodes with triple-zone JTE achieve a maximum breakdown voltage of 1.27 kV, significantly higher than those with single-zone JTE structure. The triple-zone JTE design provides a wider window for fabrication processing and epitaxial wafer growth, making it promising for cost-effective fabrication of GaN power electronics.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Bixuan Wang, Ruizhe Zhang, Hengyu Wang, Quanbo He, Qihao Song, Qiang Li, Florin Udrea, Yuhao Zhang
Summary: We propose a new circuit method to characterize the gate dynamic breakdown voltage (BVdyn) of Schottky-type p-gate GaN HEMTs in power converters. This method involves a resonance-like gate ringing and an inductive switching in the drain-source loop. The results show that the gate BVdyn decreases with increasing pulse width but saturates at 21-22 V. Additionally, the gate BVdyn increases with temperature and is higher under hard switching conditions.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Physics, Applied
Kazuki Nomoto, Wenshen Li, Bo Song, Zongyang Hu, Mingda Zhu, Meng Qi, Vladimir Protasenko, Zexuan Zhang, Ming Pan, Xiang Gao, Hugues Marchand, Wayne Johnson, Debdeep Jena, Huili Grace Xing
Summary: This study demonstrates near-ideal forward and reverse characteristics in GaN power devices using polarization-induced (Pi) doping, highlighting the potential benefits of Pi-doped GaN power devices.
APPLIED PHYSICS LETTERS
(2022)
Article
Optics
Qifeng Lyu, Huaxing Jiang, Kei May Lau
Summary: The study demonstrates the first integration of monolithically integrated UV LEDs and visible-blind UV PDs on Si substrate, achieving high sensitivity and low dark current. By optimizing the structure and materials, it offers potential for various applications with high-performance UV PDs and LEDs.
Article
Physics, Multidisciplinary
Amanpreet Kaur, Ravi Chand Singh
Summary: By inducing self-doping through asymmetrical structures, we successfully fabricated atomically thin p-n homojunction diodes in graphene without the need for traditional processes like ion implantation. The diode exhibited satisfactory rectifying properties and holds potential for future applications.
Article
Engineering, Electrical & Electronic
Dan Zhang, Chaochao Fu, Jing Xu, Chao Zhao, Jianfeng Gao, Yaodong Liu, Menghua Li, Junfeng Li, Wenwu Wang, Dapeng Chen, Tianchun Ye, Dongping Wu, Jun Luo
Summary: This paper discusses the method of using dopant segregation technique to adjust the Schottky barrier heights of NiSi/Si diodes, and presents a technique to distinguish different types of diodes.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Engineering, Electrical & Electronic
Chen Yang, Houqiang Fu, Kai Fu, Tsung-Han Yang, Jingan Zhou, Jossue Montes, Yuji Zhao
Summary: This paper investigates low-leakage hydrogen plasma (HP) terminated GaN-on-GaN vertical p-n diodes, achieving significant reductions in leakage current and improvements in breakdown voltage with a p-GaN extension design. The devices demonstrate non-destructive breakdown voltage of 1.68 kV, specific on-resistance of 0.40 MΩcm², and Baliga's figure of merit of 7.1 GWcm(-2), showing the effectiveness of HP termination with p-GaN extension in enhancing the performance of vertical GaN power diodes.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Qian Yang, Degang Zhao, Jing Yang, Zongshun Liu, Lihong Duan, Desheng Jiang
Summary: The failure analysis of a GaN p-i-n diode is conducted using various tests, and it is found that nanotubes play a significant role in the luminous spot and reduction of breakdown threshold voltage.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Article
Engineering, Electrical & Electronic
Lifeng Yuan, Feng Zhou, Yulei Jin, Qunsi Yang, Weizong Xu, Fangfang Ren, Dong Zhou, Dunjun Chen, Rong Zhang, Youdou Zheng, Hai Lu
Summary: This work reports the overvoltage ruggedness of p-gate GaN HEMTs in the 3rd-quadrant and reveals their inferior breakdown performance under blocking conditions. The unusual degradation behavior can be explained by the trapping-related carrier transport mechanism, supported by temperature-dependent breakdown characteristics.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2022)
Article
Optics
Longheng Qi, Xu Zhang, Wing Cheung Chong, Kei May Lau
Summary: This paper demonstrates a monolithic full-color micro-LED microdisplay with a resolution of 423 pixels per inch by integrating a blue GaN-on-Si display module and a quantum dots photoresist color conversion module. The result is a full-color micro-LED display with a wide color gamut and high brightness. The prototype shows potential scalability and low-cost volume production of high-resolution full-color micro-LED microdisplays.
PHOTONICS RESEARCH
(2023)
Article
Physics, Applied
Renqiang Zhu, Huaxing Jiang, Chak Wah Tang, Kei May Lau
Summary: This work presents the performance of GaN quasi-vertical trench MOSFETs grown on 6-inch Si substrates. The device with single-trench design achieves high ON-resistance, drain current density, and breakdown voltage through fine-tuning of channel doping and thick bottom dielectric process. The large-area GaN-on-Si trench MOSFET with multiple-finger design also exhibits good performance.
APPLIED PHYSICS EXPRESS
(2022)
Article
Engineering, Electrical & Electronic
Jing Wang, Leidang Zhou, Xing Lu, Liang Chen, Zimin Chen, Xinbo Zou, Gang Wang, Boming Yang, Xiaoping Ouyang
Summary: In this study, ultrafast X-ray detectors were fabricated using a high resistivity unintentionally-doped epsilon-Ga2O3 film grown on sapphire by metal-organic chemical vapor deposition (MOCVD). The detector exhibited low dark current and high sensitivity, with stable and repeatable transient response under switching X-ray illumination. Furthermore, the detector achieved pulsed X-ray detection with a narrow time resolution. These results demonstrate the great potential of MOCVD-grown high-resistivity epsilon-Ga2O3 film for ultrafast X-ray detection.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Luyu Wang, Zhiyang Xie, Beibei Pan, Zhiqi Zhou, Linze Li, Xinbo Zou, Haiming Ji, Baile Chen
Summary: We present a novel 850 nm high-speed photodetector that can simultaneously achieve high-speed data acquisition and electrical power generation. It is based on a GaAs/AlGaAs modified uni-traveling carrier photodetector (MUTC-PD). Compared to traditional p-i-n photodetectors with the same absorber thickness, the MUTC device exhibits a high 3 dB bandwidth of 11.9 GHz and a power conversion efficiency of 38.5% under a forward bias of +0.7 V. This exceptional performance is achieved by incorporating the MUTC structure on LPC devices. The device is expected to find applications in simultaneous lightwave information and power transfer, offering a potential solution for next-generation combined power and data transceiver modules.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Chemistry, Physical
Yuxin Deng, Ziqi Yang, Tongling Xu, Huaxing Jiang, Kar Wei Ng, Chao Liao, Danni Su, Yanli Pei, Zimin Chen, Gang Wang, Xing Lu
Summary: Due to the difficulty of p-type doping in beta-Ga2O3, the NiO/beta-Ga2O3 heterojunction is considered as a promising candidate for bipolar devices. In this study, the band alignment and electrical properties of NiO/beta-Ga2O3 heterojunctions with different beta-Ga2O3 orientations were comparatively studied. It was found that there is a type-II band alignment between NiO and beta-Ga2O3, and the valence band offsets and conduction band offsets vary with different substrate orientations. The influence of substrate orientations on the properties of NiO/beta-Ga2O3 heterojunctions is of great importance for the design and optimization of beta-Ga2O3-based heterojunction devices.
APPLIED SURFACE SCIENCE
(2023)
Article
Engineering, Electrical & Electronic
Yujia Tu, Weiqu Chen, Zhipeng Zhang, Zimin Chen, Yanli Pei, Gang Wang, Xing Lu
Summary: This letter presents the demonstration of surface acoustic wave (SAW) resonators using a novel epsilon-Ga2O3 piezoelectric semiconductor. A 1-mu m thick phase-pure epsilon-Ga2O3 film was grown on sapphire through metal organic chemical vapor deposition (MOCVD) and fabricated into a single-port SAW resonator with a wavelength of 2.4 mu m. The Rayleigh and Sezawa wave propagation was observed at 1.36 and 2.29 GHz, respectively, through finite element method (FEM) simulation. The study also examined the phase velocities (Vp), electromechanical coupling coefficients (K2), and quality factors (Q) of the fabricated device for both resonate modes.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Physics, Applied
Jie Li, Ying Xue, Zhao Yan, Yu Han, Kei May Lau
Summary: To achieve fully integrated silicon photonics, reliable III-V light sources that can efficiently couple with Si/SiN waveguides are crucial. A selective regrowth scheme was developed on a monolithic InP/SOI platform to construct on-chip lasers that can be efficiently coupled with Si/SiN waveguides. Strong photoluminescence emission at the telecom band was obtained on both growth templates, demonstrating the potential for multi-wavelength emission on the same chip. The regrowth method provides a promising solution for the monolithic integration of III-V on-chip lasers on Si.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Optics
Qi Lin, Jie Huang, Liying Lin, Wei Luo, Wen Gu, Kei May Lau
Summary: This article reports on the continuous wave lasing of 980nm electrically pumped quantum well lasers directly grown on silicon, and compares them with lasers grown on other substrates. The results show that although lasers grown on silicon have slightly higher threshold current, it still demonstrates a promising step towards realizing quantum well lasers on silicon.
Article
Optics
Xuetong Zhou, Ying Xue, Fan Ye, Ziyao Feng, Yuan Li, Xiankai Sun, Kei May Lau, Hon Ki Tsang
Summary: We propose and validate a new approach for high coupling efficiency (CE) grating couplers (GCs) in the lithium niobate on insulator photonic integration platform. Enhanced CE is achieved by increasing the grating strength using a high refractive index polysilicon layer on the GC. The optical cavity formed in the vertical direction enhances the CE of the waveguide GC, and simulations predict a CE of -1.40 dB while the experimentally measured CE is -2.20 dB with a 3-dB bandwidth of 81 nm from 1592 nm to 1673 nm. The high CE GC is achieved without using bottom metal reflectors or requiring the etching of the lithium niobate material.
Article
Engineering, Electrical & Electronic
Junmin Jiang, Xu Zhang, Xun Liu, Zhaojun Liu, Liusheng Sun, Shing Hin Yuen, Wing Cheung Chong, Wing-Hung Ki, C. Patrick Yue, Kei May Lau
Summary: This paper demonstrates a fully-integrated active matrix light-emitting diode (AMLED) micro-display system. The system consists of a 36 x 64 AMLED array chip based on GaN-on-Silicon epilayers and a silicon driving chip integrating an on-chip hybrid voltage regulator, pixel drivers, and peripheral circuits. The system achieves high pixel density and can operate directly with a battery without any external passive components.
IEEE JOURNAL ON EMERGING AND SELECTED TOPICS IN CIRCUITS AND SYSTEMS
(2023)
Article
Engineering, Electrical & Electronic
Junmin Zhou, Haowen Guo, Haitao Du, Yu Zhang, Haolan Qu, Wei Huang, Jianjun Zhou, Zhiqiang Xiao, Xinbo Zou
Summary: The low-noise amplification performance of an enhancement-mode p-GaN gate HEMT has been thoroughly investigated in this study, demonstrating its potential for low noise amplifier applications.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Yu Zhang, Yitian Gu, Jiaxiang Chen, Yitai Zhu, Baile Chen, Huaxing Jiang, Kei May Lau, Xinbo Zou
Summary: The OFF-state stress-induced threshold voltage instability and dynamic ON-resistance of GaN MOSHEMT with ZrO2 gate dielectric are investigated. Electron emission at the ZrO2/AlGaN interface is found to cause the threshold voltage shift. The activation energies of emission and capture are extracted by threshold voltage transient spectroscopy. Under OFF-state drain-source bias stressing, the drain current decreases despite the negative shift of threshold voltage, which is related to electron capture in the access region. The results suggest that high-quality ZrO2 is an attractive option for the gate dielectric of GaN MOSHEMTs in power switching electronics.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Optics
Longheng Qi, Peian Li, Xu Zhang, Ka Ming Wong, Kei May Lau
Summary: A prototype of full-color micro-LED micro-display with a pixel density of 391 ppi is demonstrated using InGaN/AlGaInP heterogeneous integration. This display shows the feasibility and prospects of high brightness, good color performance, and high-resolution micro-LED micro-displays in future metaverse applications.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Review
Chemistry, Analytical
Xiazhi Zou, Jiayi Yang, Qifeng Qiao, Xinbo Zou, Jiaxiang Chen, Yang Shi, Kailin Ren, Zeheng Wang, Jing-Kai Huang
Summary: Gallium nitride (GaN) high-electron-mobility transistors (HEMTs) have promising potential for power devices due to their superior advantages, but stability and reliability issues related to traps have limited their development. This article summarizes the locations and energy levels of traps in GaN HEMTs, and reviews the characterization techniques for bulk traps and interface traps.