Article
Physics, Applied
Sudipto Saha, Lingyu Meng, A. F. M. Anhar Uddin Bhuiyan, Ankit Sharma, Chinmoy Nath Saha, Hongping Zhao, Uttam Singisetti
Summary: This study presents a novel approach for growing current blocking layers for vertical gallium oxide devices and characterizes their performance through electrical tests and simulations. The results demonstrate that the current blocking layers exhibit good blocking characteristics and optimized performance.
APPLIED PHYSICS LETTERS
(2023)
Article
Crystallography
Maolin Zhang, Zeng Liu, Lili Yang, Jiafei Yao, Jing Chen, Jun Zhang, Wei Wei, Yufeng Guo, Weihua Tang
Summary: This review article summarizes recent advances in the experimental and theoretical research on β-Ga2O3-based power devices, providing comprehensive guidance for further development by discussing the operating mechanisms and obstacles to be addressed.
Review
Physics, Applied
Chenlu Wang, Jincheng Zhang, Shengrui Xu, Chunfu Zhang, Qian Feng, Yachao Zhang, Jing Ning, Shenglei Zhao, Hong Zhou, Yue Hao
Summary: Gallium oxide (Ga2O3) is an emerging ultra-wide-bandgap semiconductor with desirable properties, widely used in power electronics and solar-blind ultraviolet photodetectors. This article reviews the latest advances in beta-Ga2O3 power device technologies and discusses solutions to challenging issues in the field.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Materials Science, Coatings & Films
William A. Callahan, Edwin Supple, David Ginley, Michael Sanders, Brian P. Gorman, Ryan O'Hayre, Andriy Zakutayev
Summary: Beta gallium oxide (beta-Ga2O3) shows great potential for high-temperature, high-power, and sensing electronics applications. However, stable metallization layers for Ohmic contacts at high temperatures have been a challenge. In this study, we demonstrate stable Ohmic contacts for Ga2O3 devices operating at temperatures up to 500-600 degrees C using ultrathin Ti layers with a self-limiting interfacial reaction.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Review
Physics, Applied
Yuan Qin, Zhengpeng Wang, Kohei Sasaki, Jiandong Ye, Yuhao Zhang
Summary: Benefitted from progress on the large-diameter Ga2O3 wafers and processing techniques, Ga2O3 power device technology has rapidly advanced for power electronics applications. Reports on large-area Ga2O3 power devices have emerged globally, going beyond device demonstration to packaging, testing, and evaluation. Ga2O3 is the only wide bandgap semiconductor reaching these milestones for power device development. This paper provides a timely review on ampere-class Ga2O3 power devices, covering their electrical performance, switching characteristics, packaging and thermal management, and ruggedness and reliability.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Review
Materials Science, Multidisciplinary
Chowdam Venkata Prasad, You Seung Rim
Summary: Beta-Gallium oxide (beta-Ga2O3) has emerged as a promising semiconductor material for power electronic devices due to its ultra-wide bandgap and diverse material systems. This review article discusses recent investigations on the interface engineering of beta-Ga2O3-based power devices, summarizing different methods for improving performances and addressing challenges such as p-type doping difficulty and low thermal conductivity. The study also highlights the potential of ion-cutting process for achieving full potential of beta-Ga2O3 in power electronics.
MATERIALS TODAY PHYSICS
(2022)
Review
Chemistry, Analytical
Jiancheng Mo, Ronny Priefer
Summary: Tremors are a common movement disorder that greatly impacts patients' quality of life. While pharmacotherapies are suboptimal in managing tremor, surgical interventions like deep brain stimulation offer durable control but are limited by costs and perceived risks. Medical devices can bridge the gap between lifestyle interventions, pharmacotherapies, and surgical treatments to provide safe and effective tremor suppression.
Review
Energy & Fuels
Avneesh Kumar, Dong Wook Chang, Jong-Beom Baek
Summary: This review examines the application of artificially developed hybrid materials in water-splitting reactions, including organic (macro)molecules and perovskites. The review highlights efficient integration of organic-inorganic hybrid molecular systems within electrocatalysis devices to extract energy from water.
Article
Environmental Studies
Iker Zudaire, Gala Moreno, Jefferson Murua, Paul Hamer, Hilario Murua, Mariana T. Tolotti, Marlon Roman, Martin Hall, Jon Lopez, Maitane Grande, Gorka Merino, Lauriane Escalle, Oihane C. Basurko, Manuela Capello, Laurent Dagorn, Maria Lourdes Ramos, Francisco J. Abascal, Jose Carlos Baez, Pedro J. Pascual-Alayon, Santiago Deniz, Josu Santiago
Summary: The structure, materials and designs of drifting Fish Aggregating Devices (dFADs) have remained relatively unchanged since the 1980s, but recently there has been an increase in their size and the use of plastic components. However, the abandoned dFADs can contribute to global marine litter problem. The solution to reducing marine pollution from industrial tuna fisheries that rely on dFADs includes transitioning to biodegradable and non-toxic materials, but more research and clarity on regulations, standards, and alternatives are needed.
Review
Engineering, Biomedical
Sara J. Photiadis, Rebecca C. Gologorsky, Deepika Sarode
Summary: Type 1 diabetes mellitus is a common and highly morbid disease without a cure. Current treatments involve insulin administration and transplantation, which have limitations and risks. A bioartificial pancreas, providing total endocrine pancreatic function without immunosuppression, is a potential therapy being developed to address these challenges.
Review
Materials Science, Multidisciplinary
Chirag Gupta, Shubhra S. Pasayat
Summary: Wide bandgap semiconductors, such as GaN and SiC, are gaining traction in the power semiconductor markets. Vertical GaN and Ga2O3 offer highly energy-efficient solutions for medium and high-voltage applications, but still face challenges that need to be addressed for further advancements.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Review
Physics, Applied
Rajesh Kumar, Devesh K. Pathak, Anjali Chaudhary
Summary: The modern era is characterized by the influence of science and technology on all aspects of life. The design and development of smart devices depend on a strong scientific understanding of basic principles, driving progress in electronics and materials science. Electrochromic devices represent a simple yet intelligent application of technology, with the potential for various uses.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Review
Pharmacology & Pharmacy
Connor O'Farrell, Konstantinos Stamatopoulos, Mark Simmons, Hannah Batchelor
Summary: The development of orally ingestible medical devices requires the use of models that simulate the gastrointestinal environment on both a macro and micro scale. Various in vitro tools are available for characterizing these devices, each with its own benefits and limitations. The selection of models for evaluation should be based on the functionality and mechanism of the device.
ADVANCED DRUG DELIVERY REVIEWS
(2021)
Review
Pharmacology & Pharmacy
Konstantinos Stamatopoulos, Connor O'Farrell, Mark Simmons, Hannah Batchelor
Summary: Evaluation of orally ingestible devices is crucial for optimizing performance, with animal models providing useful information but the selection of the most appropriate species being key due to differences in gastrointestinal physiology. There is a shift towards in vitro and in silico models over animal models for better control and reproducibility, while acknowledging that animal models still offer valuable insights in certain cases.
ADVANCED DRUG DELIVERY REVIEWS
(2021)
Article
Engineering, Electrical & Electronic
Dawei Wang, Dinusha Herath Mudiyanselage, Houqiang Fu
Summary: This work presents a comprehensive design and modeling of enhancement-mode betaphase gallium oxide current-aperture vertical electron transistors (CAVETs) using TCAD simulation. It proposes a new type of CAVETs, called high electron mobility transistors (HEMT)-CAVETs, which incorporates a delta-doped ss-(AlxGa1-x)(2)O-3/Ga2O3 heterostructure. The HEMT-CAVETs demonstrate significant improvements in electron modulation, ON-state resistance (RON), and leakage, making them promising for high-power, high-voltage, and high-frequency applications. The study systematically investigates the effects of doping, channel length, and aperture length on the device performance, as well as studies the off-state leakage in the ss-Ga2O3 CAVETs for the first time. The results provide important insights for the future development of low RON ss-Ga2O3 CAVETs.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Physics, Applied
Xiang Zheng, Taylor Moule, James W. Pomeroy, Masataka Higashiwaki, Martin Kuball
Summary: A new method for measuring temperature in semiconductor devices is proposed in this study, with a focus on minimizing the interference from trapping effects. Results show that there is a certain degree of error in the channel temperature measured using drain current, with the actual channel temperature being the average value between the source and drain contacts.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Jianbo Liang, Daiki Takatsuki, Masataka Higashiwaki, Yasuo Shimizu, Yutaka Ohno, Yasuyoshi Nagai, Naoteru Shigekawa
Summary: In this work, Ga2O3(001)/Si(100) and Ga2O3(010)/Si(100) heterointerfaces were fabricated through surface activated bonding at room temperature. The thermal stability of the heterointerfaces was investigated by heating the bonding samples at different temperatures and it was found that the heterointerface with a thin Si exhibited good thermal stability at 1000 degrees C. An intermediate layer was formed at both heterointerfaces, with the Ga2O3(001)/Si(100) heterointerface having a uniform thickness while the Ga2O3(010)/Si(100) heterointerface having a non-uniform thickness.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Zhenwei Wang, Daiki Takatsuki, Jianbo Liang, Takahiro Kitada, Naoteru Shigekawa, Masataka Higashiwaki
Summary: We studied the electrical properties of n-Si/n-Ga2O3 heterojunctions fabricated by surface-activated bonding. By analyzing temperature-dependent current density-voltage characteristics, we obtained the energy barrier heights at the Si/Ga2O3 interface for different reverse voltages. The conduction band offset at the heterointerface was estimated, and the non-uniform distribution of charged interface states was found to contribute to the spatially inhomogeneous energy barrier heights. The density of shallow interface states was also extracted from the reverse current density-voltage characteristics.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Andrew J. Green, James Speck, Grace Xing, Peter Moens, Fredrik Allerstam, Krister Gumaelius, Thomas Neyer, Andrea Arias-Purdue, Vivek Mehrotra, Akito Kuramata, Kohei Sasaki, Shinya Watanabe, Kimiyoshi Koshi, John Blevins, Oliver Bierwagen, Sriram Krishnamoorthy, Kevin Leedy, Aaron R. Arehart, Adam T. Neal, Shin Mou, Steven A. Ringel, Avinash Kumar, Ankit Sharma, Krishnendu Ghosh, Uttam Singisetti, Wenshen Li, Kelson Chabak, Kyle Liddy, Ahmad Islam, Siddharth Rajan, Samuel Graham, Sukwon Choi, Zhe Cheng, Masataka Higashiwaki
Summary: Gallium Oxide has become a leading ultra-wide band gap semiconductor technology due to its favorable material properties. This roadmap presents the current state-of-the-art and future challenges in the field, aiming to enhance device performance and design efficient microelectronic systems.
Article
Physics, Applied
Sandeep Kumar, Hisashi Murakami, Yoshinao Kumagai, Masataka Higashiwaki
Summary: This study presents vertical Ga2O3 Schottky barrier diodes (SBDs) with a staircase field plate on a deep trench filled with SiO2, which effectively alleviates electric field concentration in the Ga2O3 drift layer and the SiO2 layer at high reverse voltage operation. The Ga2O3 SBDs demonstrate superior device characteristics with low on-resistance and high off-state breakdown voltage.
APPLIED PHYSICS EXPRESS
(2022)
Article
Physics, Applied
Ken Goto, Hisashi Murakami, Akito Kuramata, Shigenobu Yamakoshi, Masataka Higashiwaki, Yoshinao Kumagai
Summary: The influence of substrate orientation on the homoepitaxial growth of beta-gallium oxide was investigated. It was found that the growth rate increased near the (001) substrate, but sharply decreased from (001) to (010) with triangular pits formed on the grown layer. The pits were found to originate from dislocations propagating in the substrate at an angle of 60° with respect to the (001) plane. A pit-free homoepitaxial layer was achieved when the substrate orientation was around 60°.
APPLIED PHYSICS LETTERS
(2022)
Editorial Material
Physics, Applied
Joel B. Varley, Bo Shen, Masataka Higashiwaki
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Kyohei Nitta, Kohei Sasaki, Akito Kuramata, Hisashi Murakami
Summary: This study uses Trihalide Vapor Phase Epitaxy (THVPE) with solid GaCl3 as a group III precursor to successfully grow beta-Ga2O3, showing a linear increase in growth rate with increasing precursor pressure. The relationship between growth rate and VI/III ratio is investigated on sapphire substrates, with the maximum growth rate achieved at a VI/III ratio of 95. A growth rate of 32.2 μm/h is achieved on beta-Ga2O3 (001) substrates, with no particle generation, equivalent crystal quality to the substrate, and high purity comparable to HVPE.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Rie Togashi, Ken Goto, Masataka Higashiwaki, Yoshinao Kumagai
Summary: Thermodynamic analyses were performed to study the growth of group-III sesquioxides by ozone and plasma-assisted MBE. The driving force for III2O3 growth increased with increasing input partial pressure of the group-III metal under O-rich conditions, but decreased under group-III-metal-rich conditions. This decrease was caused by the formation of Ga2O or In2O during growth. Ga and In droplets formed at low temperatures, while Al droplets were formed at high temperatures, with the growth order being c-In2O3 < ss-Ga2O3 << alpha-Al2O3.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Zhenwei Wang, Takahiro Kitada, Daiki Takatsuki, Jianbo Liang, Naoteru Shigekawa, Masataka Higashiwaki
Summary: In this study, p-Si/n-Ga2O3 and p(+)-Si/n-Ga2O3 heterostructures were fabricated using surface-activated bonding technique, and their electrical properties were investigated. Current density-voltage measurement before and after thermal annealing at 450 ? showed a significant increase in current density after annealing, which was attributed to thinning of the intermediate layer formed during the bonding process. Distinctive two-stage capacitance-voltage characteristics were observed for p-Si/n-Ga2O3 heterostructures, and numerical calculation considering the effect of two-dimensional electron gas formed at the heterointerface reproduced these characteristics well. These results indicate that Ga2O3-based p-n heterostructures with good interface properties and large-area uniformity can be fabricated using surface-activated bonding.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Condensed Matter
Iori Kobayashi, Ryohei Hieda, Hiroto Murata, Hisashi Murakami
Summary: In this study, the impact of intermediate layers on ScAlMgO4 (SAM) for high-speed InGaN growth using trihalide vapor-phase epitaxy (THVPE) was investigated. The coverage and thickness of the intermediate layer significantly affected the composition and crystalline quality. THVPE was successfully used to fabricate InGaN with 17% indium on SAM in a lattice-matched state, demonstrating the potential for high-quality InGaN quasi-substrates with high indium composition.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2023)
Article
Materials Science, Coatings & Films
Takumi Ohtsuki, Masataka Higashiwaki
Summary: We systematically studied the relationship between the structural properties of (AlxGa1-x)(2)O-3 thin films grown on ss-Ga2O3 (010) substrates and the composition of Al. Crystal structure characterization was performed using X-ray diffraction, and surface morphology was observed using reflection high-energy electron diffraction and atomic force microscopy. Defects appeared on the surface and crystallinity began to degrade when the Al composition x exceeded approximately 0.16 in the 100-nm-thick thin films. The defects mainly developed along the [201] direction and slightly along the [001] direction as x increased. The boundary where the thin film quality changed was close to a critical thickness curve calculated using the Matthews-Blakeslee model assuming the slip system of <201>{10(2) over bar}.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
C. De Santi, M. Fregolent, M. Buffolo, M. Higashiwaki, G. Meneghessoa, E. Zanonia, M. Meneghinia
Summary: This paper analyzes the electrical behavior and deep levels in nitrogen-implanted gallium oxide Schottky barrier diodes. The study investigates the feasibility of nitrogen implantation as an isolation procedure and the annealing process to eliminate defects. The results show a reduction in leakage current and the presence of electron trapping processes. The concentration of defects decreases with high-temperature annealing.
OXIDE-BASED MATERIALS AND DEVICES XIII
(2022)
