Article
Physics, Applied
Changkun Zeng, Weizong Xu, Yuanyang Xia, Ke Wang, Fangfang Ren, Dong Zhou, Yiheng Li, Tinggang Zhu, Dunjun Chen, Rong Zhang, Youdou Zheng, Hai Lu
Summary: This study demonstrates the successful implementation of high-quality gate current blocking performance in GaN HEMTs through the development of dopant-free p-type polarization doping technique, improving the reliability of gate circuits.
APPLIED PHYSICS EXPRESS
(2022)
Article
Physics, Applied
Hong-Quan Nguyen, Thanh Nguyen, Philip Tanner, Tuan-Khoa Nguyen, Abu Riduan Md Foisal, Jarred Fastier-Wooller, Tuan-Hung Nguyen, Hoang-Phuong Phan, Nam-Trung Nguyen, Dzung Viet Dao
Summary: The study demonstrates the effect of stress or strain on the electronic characteristics of a normally off AlGaN/GaN HEMT and its potential as a highly sensitive pressure sensor with a strain sensitivity of 1250ppm(-1).
The change in drain current is most pronounced when the gate bias is near-threshold and the drain bias is slightly larger than the saturation bias.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Minghua Zhu, Catherine Erine, Jun Ma, Mohammad Samizadeh Nikoo, Luca Nela, Pirouz Sohi, Elison Matioli
Summary: This letter presents a new concept for normally-off AlGaN/GaN-on-Si MOS-HEMTs, utilizing the combination of p-GaN, tri-gate, and MOS structures to achieve high threshold voltage and low on-resistance. The design enables excellent channel control capability, higher ON/OFF ratio, and smaller sub-threshold slope compared to similar planar p-GaN devices, showcasing promising prospects for future power electronics applications.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Yaozong Zhong, Shuai Su, Xin Chen, Yu Zhou, Hongwei Gao, Xiaoning Zhan, Xiaolu Guo, Shuming Zhang, Qian Sun, Hui Yang
Summary: The reliability and degradation mechanism of normally OFF high-electron-mobility transistors (HEMTs) with regrown p-GaN gates and AlN/SiNx stack passivation were studied. It was found that the Schottky junction fails first, leading to a sudden increase in gate current, highlighting the need for improving gate breakdown voltage and lifetime. The analyses suggest the feasibility of using regrown p-GaN gates and AlN/SiNx stack passivation in practical applications.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Chia-Hao Liu, Hsien-Chin Chiu, Hsiang-Chun Wang, Hsuan-Ling Kao, Chong-Rong Huang
Summary: The study shows that DJ-HEMT exhibits higher gate voltage swing in the gate region due to the dual junction, enhancing gate performance. Compared to ST-HEMT, DJ-HEMT has higher V-TH, saturation current, I-ON/I-OFF ratio, and gate swing voltage. In addition, DJ-HEMT also has lower leakage current and longer lifetime measurement.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Nengtao Wu, Ling Luo, Zhiheng Xing, Shanjie Li, Fanyi Zeng, Ben Cao, Changtong Wu, Guoqiang Li
Summary: This article investigates a low-leakage-current and high-breakdown-voltage normally OFF p-GaN gate HEMT on a Si substrate with low-damage NH3 plasma pretreatment. The NH3 plasma pretreatment effectively removes surficial oxides and other impurities, suppresses interface traps, and reduces the overall drain leakage current. The NH3 plasma pretreated p-GaN gate HEMTs exhibit a high ON/OFF-current ratio, low reverse gate leakage current, high gate breakdown voltage, and high breakdown voltage at 1 mu A/mm.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Huaxing Jiang, Qifeng Lyu, Renqiang Zhu, Peng Xiang, Kai Cheng, Kei May Lau
Summary: This article demonstrates the research results of p-GaN gate HEMTs with ultrahigh breakdown voltage and excellent performance on silicon, proving their great potential for applications beyond 600V.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Physics, Applied
Xin Chen, Yaozong Zhong, Xiaolu Guo, Shumeng Yan, Yu Zhou, Shuai Su, Hongwei Gao, Xiaoning Zhan, Zihui Zhang, Wengang Bi, Qian Sun, Hui Yang
Summary: Two types of normally-off high-electron-mobility transistors with regrown p-GaN gate were studied for the influence of traps on reverse gate leakage. Different acceptor traps in the p-GaN/AlGaN/GaN junction significantly impact carrier behaviors, thus affecting the leakage mechanisms. The presence of traps at different energy levels has been confirmed to lead to variations in the reverse gate leakage behavior.
APPLIED PHYSICS EXPRESS
(2021)
Article
Materials Science, Multidisciplinary
Shaoqian Lu, Guohao Yu, Yingfei Sun, Xu Yuan, Zhongkai Du, Bingliang Zhang, Lu Wang, Yu Li, Dongdong Wu, Zengli Huang, Zhongming Zeng, Xulei Qin, Baoshun Zhang
Summary: In this article, a method of nitrogen plasma treatment is proposed to achieve normally off p-GaN/AlGaN/GaN high-electron-mobility transistors, and the related mechanism is proposed. The nitrogen plasma treatment depletes holes in the p-GaN layer and changes the surface characteristics, resulting in the formation of a 2D electron gas at the AlGaN/GaN interface. The device shows enhanced performance with improved threshold voltage, on/off ratio, and maximum drain current.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Hsiang-Chun Wang, Taofei Pu, Xiaobo Li, Chia-Hao Liu, JunYe Wu, JiaYing Yang, Ziyue Zhang, Youming Lu, Qi Wang, Lijun Song, Hsien-Chin Chiu, Jin-Ping Ao, Xinke Liu
Summary: In this study, a normally-OFF AlGaN/GaN HEMT on a free-standing GaN substrate was fabricated, and excellent performance was achieved using self-terminated etching technology. Compared to Si-HEMT, this HEMT demonstrated higher current density, lower subthreshold swing and drain leakage current, and lower ON-resistance.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Materials Science, Multidisciplinary
Krishna Sai Sriramadasu, Yue-Ming Hsin
Summary: This study presents a normally-off dual-gate AlGaN/GaN high-electron-mobility transistor. The optimized thickness and length of the AlGaN layer under the second gate significantly impact the maximum drain current and the off-state breakdown conditions. The reverse conduction characteristic is also improved by establishing a freewheeling path between the second gate and the drain.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Huan Wang, Yan Lin, Junsong Jiang, Dan Dong, Fengwei Ji, Meng Zhang, Ming Jiang, Wei Gan, Hui Li, Maojun Wang, Jin Wei, Baikui Li, Xi Tang, Cungang Hu, Wenping Cao
Summary: This article investigates the thermally induced threshold voltage shift in p-GaN gate high-electron-mobility transistors (HEMTs), observing different types of shift in different gate types at elevated temperatures. Proposed mechanisms and experimental verification were presented.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Xing Wei, Xiaodong Zhang, Chi Sun, Wenxin Tang, Chunhong Zeng, Fu Chen, Tao He, Guohao Yu, Liang Song, Wenkui Lin, Xuan Zhang, Desheng Zhao, Wei Huang, Yong Cai, Baoshun Zhang
Summary: In this article, normally-OFF etching-free p-GaN stripe array gate AlGaN/GaN high-electron-mobility-transistors (PSAG-HEMTs) are designed and experimentally demonstrated through hydrogen plasma treatment. A unique threshold voltage modulation technique is proposed based on the PSAG structure, allowing continuous V-TH shift by tuning the widths of p-GaN and hydrogenatedp-GaN stripes. By extending the PSAG to the drain side based on 3-D simulation results, improvements in breakdown voltage and enhanced conductivity effect are observed, resulting in a low ON-resistance. The fabricated PSAG-HEMT exhibits significant improvements over Reference single-gate E-mode and D-mode devices, showcasing a promising architecture for future high voltage normally-OFF p-GaN HEMT devices.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Biochemistry & Molecular Biology
Hsien-Chin Chiu, Chia-Hao Liu, Chong-Rong Huang, Chi-Chuan Chiu, Hsiang-Chun Wang, Hsuan-Ling Kao, Shinn-Yn Lin, Feng-Tso Chien
Summary: By growing a high-quality Al2O3/AlN layer in an HEMT, the MIS-HEMT showed improved gate leakage and threshold voltage compared to the SG-HEMT, achieving a higher turn-on voltage, better reliability, and longer lifetime.
Article
Computer Science, Information Systems
Shenglei Zhao, Jincheng Zhang, Yachao Zhang, Lansheng Feng, Shuang Liu, Xiufeng Song, Yixin Yao, Jun Luo, Zhihong Liu, Shengrui Xu, Yue Hao
Summary: This study presents a 1.7 kV normally-off p-GaN gate high-electron-mobility transistor (HEMT) on SiC substrates. The fabricated p-GaN HEMT showed a threshold voltage of 1.10V, a maximum drain current of 235 mA/mm, an ON/OFF ratio of 10^8, and a breakdown voltage of 440V with L-GD = 5 μm. With L-GD = 23 μm, the p-GaN HEMT achieved a remarkably high breakdown voltage of 1740V with substrate grounded. The results demonstrate the significant potential of p-GaN gate HEMTs on SiC substrates for high-voltage power applications.
SCIENCE CHINA-INFORMATION SCIENCES
(2023)
Article
Physics, Applied
Zhanyong Xing, Haochen Zhang, Yue Sun, Lei Yang, Kunpeng Hu, Kun Liang, Dawei Wang, Houqiang Fu, Haiding Sun
Summary: In this work, an enhancement-mode (E-mode) AlGaN/GaN-based high-electron-mobility transistor (HEMT) with a graded AlGaN cap layer (GACL) is proposed. The GACL is designed to produce high-concentration polarization-induced holes and negative net polarization charges to benefit the normally-OFF operation of the device. The optimized graded-AlGaN-gated metal-semiconductor HEMT achieves a large threshold voltage of 4 V, and shortening the gate length and inserting an oxide layer can suppress gate leakage current and enhance gate voltage swing.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Xueqiang Xiang, Li-Heng Li, Chen Chen, Guangwei Xu, Fangzhou Liang, Pengju Tan, Xuanze Zhou, Weibing Hao, Xiaolong Zhao, Haiding Sun, Kan-Hao Xue, Nan Gao, Shibing Long
Summary: In this study, high-quality β-Ga2O3 films were epitaxially grown using MOCVD with different donor concentrations, and their shallow donor states were investigated. The unintentional doping effects were found to have a significant impact on the donor states, and a method to reduce the unintentional doping effect was proposed.
SCIENCE CHINA-MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Muhammad Hunain Memon, Huabin Yu, Hongfeng Jia, Shi Fang, Danhao Wang, Haochen Zhang, Shudan Xiao, Yang Kang, Yifan Ding, Chen Gong, Haiding Sun
Summary: Optical wireless communication (OWC) systems, specifically in the solar-blind deep-ultraviolet (DUV) and visible-light (VL) band, are crucial for next-generation data transmission and acquisition due to their superior advantages in free space or underwater applications. In this study, a vertically integrated DUV micro-LED array with CdSe/ZnS blue color quantum dots is proposed to emit dual wavelengths, significantly expanding the capacity and functionality of OWC. The device achieves a bandwidth of 254 and 36 MHz and data rates of 586 and 55 Mbps using the on-off keying (OOK) modulation scheme at emission wavelengths of 275 and 470 nm, respectively. Importantly, the bit error rate is below the forward error correction threshold, demonstrating the feasibility of implementing this low-cost and compact device for practical solar-blind and VL dual-band communication, such as in marine science and ocean exploration.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Xing Wei, Wenchao Shen, Xin Zhou, Wenbo Tang, Yongjian Ma, Tiwei Chen, Dawei Wang, Houqiang Fu, Xiaodong Zhang, Wenkui Lin, Guohao Yu, Yong Cai, Baoshun Zhang
Summary: In this letter, high-performance lateral AlGaN/GaN hybrid anode diodes (HADs) with p-GaN stripe array gate (PSAG) structure are demonstrated, showing much reduced turn-on voltage (V-T) compared with reference p-GaN gate HADs. The PSAG-HADs, without field plates (FPs) or passivation, exhibited a low V-T of 0.8 V, a low reverse leakage current of 1.87 nA/mm at -1 kV, a high I-ON/I-OFF ratio of similar to 10^11, a high breakdown voltage (BV) of 2.69 kV, and a low specific ON-resistance (R-ON,R- sp) of 2.11 mΩ·cm^2. This work demonstrates the promising potential of PSAG-HADs for next-generation high-voltage high-efficiency power electronics.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Marco Nicoletto, Alessandro Caria, Carlo De Santi, Matteo Buffolo, Xuanqui Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: In this article, we extensively investigate the degradation of gallium nitride (GaN)-based high periodicity indium GaN (InGaN)-GaN multiple quantum well (MQW) solar cells under optical stress at high excitation intensity and high temperature. The obtained results suggest that the degradation originates from the diffusion of hydrogen, and the proposed analytical methodology provides insight into MQW solar cell degradation.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Chemistry, Multidisciplinary
Shi Fang, Liuan Li, Danhao Wang, Wei Chen, Yang Kang, Weiyi Wang, Xin Liu, Yuanmin Luo, Huabin Yu, Haochen Zhang, Muhammad Hunain Memon, Wei Hu, Jr-Hau He, Chen Gong, Chengjie Zuo, Sheng Liu, Haiding Sun
Summary: Underwater optical communication (UOC) is gaining significant interest due to the continuous expansion of human activities in marine/ocean environments. Self-powered photoelectrodes that are water-durable and act as a battery-free light receiver in UOC play a crucial role in facing complex underwater conditions. A self-powered photoelectrochemical (PEC) photodetector using n-type gallium nitride (GaN) nanowires as a photoelectrode, decorated with an iridium oxide (IrOx) layer for optimizing charge transfer dynamics, breaks the responsivity-bandwidth trade-off limit and achieves an ultrafast response speed and high responsivity. This device also exhibits a large bandwidth, making it one of the highest performing self-powered photodetectors in optical communication systems.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Physics, Applied
Zheming Wang, Guohao Yu, Xu Yuan, Xuguang Deng, Li Zhang, Shige Dai, Guang Yang, Liguo Zhang, Rongkun Ji, Xiang Kan, Xuan Zhang, Houqiang Fu, Zhongming Zeng, Roy K. -Y. Wong, Yong Cai, Baoshun Zhang
Summary: This study investigated the electrical characterizations of AlGaN/GaN heterojunctions isolated by N implantation at elevated temperatures. Three-terminal measurements were carried out to characterize leakage paths, and crystal lattice damage due to implantation was monitored by high-resolution x-ray diffraction. Compared with room temperature implantation, the current leakage was greatly reduced by the implantation at 300℃. The low leakage was attributed to low acceptor-like energy levels due to low crystal lattice damage by the dynamic annealing effect at high-temperature implantation. The post-annealing process increased the current leakage by two orders of magnitude, suggesting that the implantation isolation process should be conducted after higher temperature processes (> 450℃) in the fabrication of GaN devices. These results can provide valuable information for the fabrication, reliability, and mass production of various GaN-based photonics and electronics.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Haochen Zhang, Yao Chen, Yue Sun, Lei Yang, Kunpeng Hu, Zhe Huang, Kun Liang, Zhanyong Xing, Hu Wang, Mingshuo Zhang, Shiping Guo, Haiding Sun
Summary: This study investigates the effect of in situ SiNx grown with different carrier gases on the properties of SiNx/AlGaN/GaN MIS-HEMTs. It was found that SiNx grown with N-2 as carrier gas is more sensitive to growth conditions, while SiNx grown with H-2 as carrier gas is more stable. The performance of H-2-SiNx-passivated devices is improved compared to N-2-SiNx, with reduced interface-state density, improved current characteristics, reduced threshold voltage shift, and mitigated current collapse, especially after long-term electrical stress.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Coatings & Films
Dinusha Herath Mudiyanselage, Dawei Wang, Houqiang Fu
Summary: In this study, ultrawide bandgap beta-(AlxGa1-x)(2)O-3 vertical Schottky barrier diodes on (010) beta-Ga2O3 substrates were fabricated and demonstrated. The fabricated devices exhibited excellent rectification properties with a high on/off ratio, a low turn-on voltage, and a low on-resistance. The leakage mechanisms of the devices were analyzed and it was found that Poole-Frenkel emission and trap-assisted tunneling were the main mechanisms at high and low temperatures, respectively. This work provides an important reference for the future development of ultrawide bandgap beta-(AlxGa1-x)(2)O-3 power electronics, RF electronics, and ultraviolet photonics.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Materials Science, Multidisciplinary
Yuanmin Luo, Danhao Wang, Yang Kang, Shi Fang, Xin Liu, Wei Chen, Huabin Yu, Hongfeng Jia, Muhammad Hunain Memon, Haochen Zhang, Dongyang Luo, Xiyu Sun, Liuan Li, Jr-Hau He, Haiding Sun
Summary: Optoelectronic-logic-gates (OLGs) are emerging as a new logic platform that uses photons as input for faster and larger-capacity data transmission and processing. This study presents reprogrammable OLGs in a photoelectrochemical environment using gallium-nitride semiconductor p-n nanowires as photoelectrodes to achieve bidirectional photocurrent. Various binary OLGs, such as NOT, XOR, and OR, are demonstrated with the flexibility to switch their logic function by adjusting programming inputs. Ternary OLGs, including ternary OR gates, can also be achieved based on binary OLGs by tuning the applied bias for higher logic complexity.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Physics, Applied
Chengjie Zhou, Wencheng Niu, Lei Li, Dandan Hao, Hao Huang, Houqiang Fu, Xingqiang Liu, Xuming Zou, Fukai Shan, Zhenyu Yang
Summary: In this study, a multifunctional optoelectronic memory was developed by coupling Au nanoparticles with MoS2, enhancing the light absorption capacity of MoS2 and achieving excellent device performance and storage time. Based on this research, a hardware core mimicking human retinal imaging was proposed to enable advances in neuromorphic electronics, particularly in optical information sensing and learning.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Alessandro Caria, Carlo De Santi, Matteo Buffolo, Marco Nicoletto, Xuanqi Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: The aim of this article is to investigate the degradation mechanisms of GaN solar cells under harsh conditions, specifically forward current stress. The results indicate that the main parameters of the cells decrease under this stress, and there is a correlation between the charge distribution inside the active region and the concentration of trap states. The decrease in power conversion efficiency is attributed to a redistribution of charge in the active region, resulting in an increase in midgap states density. These findings fill the gap in the literature regarding the long-term reliability of GaN solar cells under harsh conditions.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Computer Science, Information Systems
Haochen Zhang, Yue Sun, Kunpeng Hu, Lei Yang, Kun Liang, Zhanyong Xing, Hu Wang, Mingshuo Zhang, Huabin Yu, Shi Fang, Yang Kang, Haiding Sun
Summary: This study reports a high-performance double heterojunction AlGaN/GaN HEMT with a decreasing-Al-composition graded AlGaN back barrier (BB) beneath the GaN channel, which improves electron confinement. The DH-HEMT shows significantly improved on-state drain current density and off-state breakdown voltage compared to the SH-HEMT. Additionally, with a SiNx passivation layer, the DH-HEMT exhibits almost constant off-state leakage current and negligible gate contact degradation across a temperature range of 25°C to 150°C. These results highlight the superiority and reliability of the proposed graded AlGaN BB to enhance device characteristics in high-temperature and harsh conditions.
SCIENCE CHINA-INFORMATION SCIENCES
(2023)
Article
Energy & Fuels
Marco Nicoletto, Alessandro Caria, Fabiana Rampazzo, Carlo De Santi, Matteo Buffolo, Giovanna Mura, Francesca Rossi, Xuanqui Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: This study investigates the influence of V-pits on the electrical performance of high periodicity InGaN-GaN multiple quantum wells solar cells. Through combined electrical analysis, microscopy investigation, and simulations, it is found that V-pits can affect the turn-on voltage and current-voltage characteristics of the solar cells. The presence of V-pits allows for a closer connection between the quantum well region and the p-side contact. These findings provide insight into the role of V-pits in the electrical performance of high-periodicity quantum well devices.
IEEE JOURNAL OF PHOTOVOLTAICS
(2023)
Article
Nanoscience & Nanotechnology
Frank Angeles, Samreen Khan, Victor H. H. Ortiz, Mingfei Xu, Shisong Luo, Dinusha Herath Mudiyanselage, Houqiang Fu, Yuji Zhao, Richard B. B. Wilson
Summary: The thermal conductivity of wide bandgap semiconductor thin films has a significant impact on the performance of various devices. However, accurately measuring the thermal conductivity of sub-micrometer thin films with high values is difficult. This study proposes a combination of magneto-optic thermometry and TiN interfacial layers to enhance the spatiotemporal resolution of pump/probe thermal transport measurements.
