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
Chemistry, Physical
Yong Ha Choi, Kwang Hyeon Baik, Suhyun Kim, Jihyun Kim
Summary: The etching process of beta-Ga2O3 semiconductor using phosphoric acid as demonstrated in this study showed an anisotropic etch pit formation along the [001] direction. The new exposed facet (-201) was found to be stable, and the optoelectronic performance was greatly improved through the effective removal of defects by PEC etching.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Wenkai Yue, Peixian Li, Xiaowei Zhou, Yanli Wang, Jinxing Wu, Junchun Bai
Summary: This study optimized the dip-coating method of SiO2 nanospheres to obtain a neatly arranged single-layer SiO2 array, and used ICP technique to etch the p-GaN layer to prepare a periodic triangular nanopore array, resulting in an LED chip with higher light output power.
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)
Review
Chemistry, Analytical
Chao-Tsung Ma, Zhen-Huang Gu
Summary: Wide-bandgap (WBG) material-based switching devices, such as gallium nitride (GaN) HEMTs and silicon carbide (SiC) MOSFETs, are promising candidates for replacing conventional silicon MOSFETs due to their higher switching frequencies and lower losses. This paper aims to provide engineers with a comprehensive understanding of the driving requirements for WBG switching devices, especially for mid- to high-power applications. The research covers characteristics, operating principles, driving circuit design considerations, and commercial products for WBG switching devices.
Article
Chemistry, Multidisciplinary
Jinyuan Xu, Ailing Chen, Linfeng Yu, Donghai Wei, Qikun Tian, Huimin Wang, Zhenzhen Qin, Guangzhao Qin
Summary: In this paper, the stable structure of a monolayer CuI with ultra-low thermal conductivity and an ultra-wide direct bandgap is predicted from first-principles calculations. This material shows potential applications in transparent and wearable electronics.
Article
Materials Science, Multidisciplinary
Wei Jia, Berardi Sensale-Rodriguez
Summary: This article discusses the potential of using lateral Schottky diodes in wide bandgap semiconductors for high-speed modulation and low-loss metamaterial configurations in order to unlock the terahertz band for future 6G wireless communications.
OPTICAL MATERIALS EXPRESS
(2022)
Review
Crystallography
Wannian Fang, Qiang Li, Jiaxing Li, Yuxuan Li, Qifan Zhang, Ransheng Chen, Mingdi Wang, Feng Yun, Tao Wang
Summary: The application of deep ultraviolet detection (DUV) in military and civil fields has gained increasing attention from researchers. Inorganic materials are widely used in DUV detection due to their good stability and controllable growth, compared to the complex molecular structure and poor stability of organic materials. Rapid advances in preparing high-quality ultrawide-bandgap (UWBG) semiconductors have enabled the development of high-performance DUV photodetectors with different geometries, overcoming disadvantages in traditional detectors. This article provides a brief introduction to the development history and types of DUV detectors, and comprehensively summarizes and reviews typical UWBG detection materials and their methods of preparation, as well as their research and application status, including III-nitride semiconductors, gallium oxide, diamond, etc. Additionally, problems related to DUV detection materials, such as material growth, device performance, and future development, are discussed.
Article
Chemistry, Physical
L. K. Nolasco, G. F. B. Almeida, T. Voss, C. R. Mendonca
Summary: This study investigates the incubation effect during fs-laser micromachining of gallium nitride films with three different wavelengths, revealing that GaN requires more overlapping pulses for incubation at green and infrared excitation, while ultraviolet excitation achieves incubation faster. Additionally, the micromachining mechanism is dominated by multiphoton ionization at 343 nm and 515 nm, while other effects such as tunneling ionization also contribute at 1030 nm.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Electrical & Electronic
Chi Zhang, Sheng Li, Weihao Lu, Siyang Liu, Yanfeng Ma, Jingwen Huang, Jiaxing Wei, Long Zhang, Weifeng Sun
Summary: This study reveals the unclamped-inductive-switching (UIS) behaviors of GaN-based high-electron-mobility transistors with p-type GaN gate (p-GaN HEMTs) at cryogenic temperature (CT). It is found that the UIS performance of p-GaN HEMTs is not affected by temperature, and the resonant circuit and inverse-piezoelectric effect are identified as key factors in the UIS process. These findings indicate the superiority of p-GaN HEMTs for special applications.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(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
Engineering, Electrical & Electronic
Yuan Qin, Ming Xiao, Ruizhe Zhang, Qingyun Xie, Tomas Palacios, Boyan Wang, Yunwei Ma, Ivan Kravchenko, Dayrl P. Briggs, Dale K. Hensley, Bernadeta R. Srijanto, Yuhao Zhang
Summary: This work presents the fabrication of quasi-vertical GaN Schottky barrier diodes (SBDs) on a 6-inch Si substrate with a record-breaking breakdown voltage (BV) of over 1 kV. The novel use of a deep mesa in quasi-vertical devices allows for a self-aligned edge termination, and the mesa sidewall is covered by p-type nickel oxide (NiO) to reduce the surface field. The device exhibits a parallel-plane junction electric field of 2.8 MV/cm, along with low turn-on voltage and specific on-resistance. Additionally, it demonstrates excellent overvoltage robustness under continuous stress.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Clint D. Frye, Scott B. Donald, Catherine E. Reinhardt, Rebecca J. Nikolic, Lars F. Voss, Sara E. Harrison
Summary: The study demonstrates that SiO2 can serve as an effective mask material for deep etching of GaN devices with high selectivity, achieving GaN:SiO2 selectivities greater than those reported for metal hard masks. Introducing Al and AlCl into the plasma enables ultrahigh SiO2 selectivities, providing a low-contamination pathway for etching deep GaN microdevices.
MATERIALS RESEARCH LETTERS
(2021)
Article
Materials Science, Coatings & Films
Lulu Guan, Xingyu Li, Chunxiang Guo, Xinying Shi, Kaidong Xu, Shiwei Zhuang
Summary: GaN/AlGaN, the third-generation semiconductor, is widely used in advanced power and RF devices. Precise and low-damage etching is crucial for preparing recessed-gate enhancement-mode GaN high electron mobility transistors. This research focuses on two self-limiting AlGaN ALE systems and provides insights into the ALE mechanism of AlGaN.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Review
Energy & Fuels
Amit Kumar, Milad Moradpour, Michele Losito, Wulf-Toke Franke, Suganthi Ramasamy, Roberto Baccoli, Gianluca Gatto
Summary: Power electronic systems using wide band gap (WBG) materials offer the potential for more efficient and higher power density power converters. This paper reviews the development and applications of SiC and GaN power devices, and discusses the associated challenges.
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
Computer Science, Software Engineering
Yi-Ting Chen, Chin-Yu Huang, Tsung-Han Yang
Summary: Software development process involves various activities for developing, testing, maintaining, and evolving a software system. However, software maintenance occupies the majority of the cost and can lead to degrading software quality. To address this issue, this study proposes a multi-pattern clustering algorithm for software modularisation. Experimental results show that the proposed algorithm improves the modularisation quality by nearly 1.6 times compared to expert decomposition and has a 13% enhancement in producing results similar to human thinking.
Article
Materials Science, Multidisciplinary
Ziyi He, Kai Fu, Mingfei Xu, Jingan Zhou, Tao Li, Yuji Zhao
Summary: A theoretical analysis of the electrical performance of ultrawide-bandgap boron nitride (BN)-based vertical junction devices, including h-BN Schottky diode, h-BN pn diode, and h-BN/AlN pn diode, is performed using technology computer-aided design simulation. This is the first demonstration of BN power devices in simulation. The results show excellent performance for h-BN junctions, especially in breakdown behaviors, providing insights for the future development of robust BN power electronics.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2023)
Article
Computer Science, Information Systems
Xiu Zhang, Baoxing Wang, Kai Fu, Rui Yue, Haojie Guo, Shuqi Li, Yong Cai
Summary: This work proposes a novel pulsating DC high-voltage linear driving scheme for GaN-based LED general lighting to save costs and reduce flicker. The superiority and practicality of this scheme in three-phase AC power grids were demonstrated for the first time. Linear driving of GaN LEDs for three-phase AC grids provides superior performance for general lighting, with a 90.7% DC component in the rectified voltage effectively alleviating flicker.
Article
Chemistry, Physical
Yuji Zhao, Mingfei Xu, Xuanqi Huang, Justin Lebeau, Tao Li, Dawei Wang, Houqiang Fu, Kai Fu, Xinqiang Wang, Jingyu Lin, Hongxing Jiang
Summary: III-nitride InGaN material is an ideal candidate for high-performance photovoltaic solar cells, especially in high-temperature applications. This paper provides a comprehensive review of recent developments in InGaN-based solar cells, including theoretical modeling, material epitaxy, device engineering, and high-temperature measurement. Substrate technology and unique properties of InGaN materials, such as polarization control and positive thermal coefficient, are highlighted. Outstanding high-temperature InGaN-based solar cells with quantum efficiency approaching 80% at 450 degrees C have been demonstrated. Future innovations in epitaxy science, device engineering, and integration methods are required to further enhance the efficiency and expand the applications of InGaN-based solar cells.
MATERIALS TODAY ENERGY
(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
Engineering, Electrical & Electronic
Prudhvi Peri, Kai Fu, Houqiang Fu, Jingan Zhou, Yuji Zhao, David J. Smith
Summary: The morphology of GaN substrates grown by HVPE and by ammonothermal methods was observed to have an impact on the performance of GaN-on-GaN p-i-n diodes. HVPE-grown substrates showed ordered surface features, while ammonothermal substrates did not. Diodes fabricated on HVPE substrates had higher reverse-bias voltages compared to those on ammonothermal substrates.
JOURNAL OF ELECTRONIC MATERIALS
(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
Engineering, Electrical & Electronic
Mengyang Yuan, John Niroula, Qingyun Xie, Nitul S. Rajput, Kai Fu, Shisong Luo, Sagar Kumar Das, Abdullah Jubair Bin Iqbal, Bejoy Sikder, Mohamed Fadil Isamotu, Minsik Oh, Savannah R. Eisner, Debbie G. Senesky, Gary W. Hunter, Nadim Chowdhury, Yuji Zhao, Tomas Palacios
Summary: This letter presents an enhancement-mode GaN transistor technology that can operate in a simulated Venus environment for 10 days. The robustness of the transistor was evaluated through in-situ electrical characterization and advanced microscopy investigation. This is the first demonstration and comprehensive analysis of E-mode GaN transistors in such harsh environments, establishing it as a strong contender for harsh environment mixed-signal electronics.
IEEE ELECTRON DEVICE 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
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.
Article
Nanoscience & Nanotechnology
Xiangkai Liu, Zhongzheng Wang, Hao Huang, Congye Liu, Wencheng Niu, Zhengdao Xie, Dandan Hao, Houqiang Fu, Xingqiang Liu, Xuming Zou, Fukai Shan, Zhenyu Yang
Summary: The integration of data storage and computing capabilities has led to the development of a microneuronal network system with high precision and speed rates. This article introduces an optoelectronic storage device based on a transistor, which enables the construction of logic gates and the simulation of future machine vision applications. The microneural network system achieves a recognition rate of 96.3% in a multidimensional color space.
ACS APPLIED NANO MATERIALS
(2023)
