Related references
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Article
Materials Science, Coatings & Films
Jian-Sian Li et al.
Summary: The characteristics of sputtered NiO for pn heterojunctions with Ga2O3 were investigated, and it was found that the oxygen/nickel and Ni2O3/NiO ratios, as well as the bandgap and resistivity, increased with the O-2/Ar gas flow ratio. However, the bandgap and Ni2O3/NiO ratio decreased with increasing annealing temperature, resulting in higher film density. The incorporation of hydrogen into NiO during plasma exposure was confirmed, and the band alignments of NiO films with both alpha- and beta-Ga2O3 were determined to have type II-staggered gaps. The breakdown voltage of NiO/beta-Ga2O3 heterojunction rectifiers also varied with the O-2/Ar flow ratio during deposition.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Physics, Applied
Ming Xiao et al.
Summary: This work presents a heterogeneous junction termination extension (JTE) based on p-type nickel oxide (NiO) for gallium oxide (Ga2O3) devices. The NiO JTE is deposited on the surface of Ga2O3 by magnetron sputtering, and consists of multiple layers with varying lengths to achieve a graded decrease in effective charge density. Experimental results show that the JTE enables a breakdown voltage over 3.2 kV and a consistent parallel-plate junction field of 4.2 MV/cm, with a power figure of merit of 2.5-2.7 GW/cm(2).
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Weibing Hao et al.
Summary: In this work, a novel conductivity-controlled junction termination extension (JTE) technique using p-type NiO is demonstrated for the potential commercialization of Ga2O3 power devices. The technique effectively suppresses the surface electric field at the Schottky edge and allows control of the concentration of p-type NiO to maximize the breakdown voltage (V-br). The beta-Ga2O3 Schottky barrier diodes (SBDs) with p-type NiO JTE show great advantages in device performance parameters, indicating the effectiveness of p-NiO JTE in reducing the fringe electric field.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Materials Science, Coatings & Films
Jian-Sian Li et al.
Summary: The effect of drift layer doping, NiO layer thickness, and extent of extension beyond the cathode contact on the performance of NiO/beta-Ga2O3 rectifiers was studied. Decreasing drift layer doping increased the reverse breakdown voltage, while increasing the NiO layer thickness reduced reverse leakage current and recovery switching time. The use of NiO to form a pn heterojunction significantly improved the breakdown voltage compared to Schottky rectifiers. Large area devices achieved high performance comparable to SiC and GaN power devices.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Materials Science, Coatings & Films
Jian-Sian Li et al.
Summary: Vertical geometry NiO/beta n-Ga2O/n(+) Ga2O3 heterojunction rectifiers with different contact sizes demonstrated high breakdown voltages up to 7.5 kV. The devices exceeded the unipolar 1D limit for SiC without requiring substrate thinning or annealing. The power figure-of-merit, V-B(2)/R-ON, was 6.2 GW cm(-2), and the average electric field strength approached the maximum for beta-Ga2O3. The rectifiers exhibited high on-off ratios and low reverse current densities, with fast reverse recovery time and high forward current density.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Crystallography
Jian-Sian Li et al.
Summary: Vertical heterojunction rectifiers with p-type NiO and thick Ga2O3 drift layers grown on Sn-doped β-Ga2O3 substrates exhibited breakdown voltages > 8 kV. Low drift doping concentration, low power during NiO deposition, and the formation of a guard ring were key factors for achieving excellent performance. These results demonstrate the potential of NiO/Ga2O3 rectifiers beyond SiC and GaN.
Review
Physics, Condensed Matter
Xing Lu et al.
Summary: Beta gallium oxide (beta-Ga2O3) with its ultra-wide bandgap and large critical electric field has potential for power electronics applications. However, the lack of p-type doping hinders its commercial use. Heterojunctions with nickel oxide (NiO) have shown promise as a solution. This review summarizes recent advances in the construction, characterization, and performance of NiO/beta-Ga2O3 heterojunction power devices.
JOURNAL OF SEMICONDUCTORS
(2023)
Article
Materials Science, Coatings & Films
William A. Callahan et al.
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)
Editorial Material
Physics, Condensed Matter
Guangwei Xu et al.
JOURNAL OF SEMICONDUCTORS
(2023)
Article
Engineering, Electrical & Electronic
Sudip K. Mazumder et al.
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)
Article
Materials Science, Multidisciplinary
Jian-Sian Li et al.
Summary: NiO/β-Ga2O3 vertical rectifiers show near-temperature-independent breakdown voltages (V-B) of >8 kV at 600 K. The power figure of merit (V-B)²/R-ON for 100 μm diameter devices is 9.1 GW cm(-2) at 300 K and 3.9 GW cm(-2) at 600 K. In contrast, Schottky rectifiers on the same wafers have V-B of about 1100 V at 300 K with a negative temperature coefficient of breakdown. The power figure of merit for Schottky rectifiers is much lower compared to the heterojunction rectifiers. The results demonstrate the potential of using transparent oxide heterojunctions for high temperature, high voltage applications.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Engineering, Electrical & Electronic
Feng Zhou et al.
Summary: The technical progress of Ga2O3 power diodes is limited by a lack of performance evaluation and reliability validation, but they have shown great potential in high-efficiency, high-power, and high-reliability applications.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Physics, Applied
Zbigniew Galazka
Summary: This Tutorial provides a detailed description of the critical aspects of bulk beta-Ga2O3 single crystal growth using the Czochralski method. It covers the thermodynamics of Ga2O3, comprehensive solutions for crystal size scale-up, the impact of free carrier absorption on growth stability, and important factors such as crystal growth direction and intentional doping. The resulting crystals' structural quality and basic physical properties are also discussed.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Andrew J. Green et al.
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
Qinglong Yan et al.
Summary: This study presents a vertical beta-Ga2O3 Schottky barrier diode with an advanced termination structure and coupled field plate structures to mitigate crowding electric field. The diode exhibits high breakdown voltage and power figure of merit, along with high-quality interface, making it promising for high power applications.
APPLIED PHYSICS LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Pengfei Dong et al.
Summary: By employing a deep trench with a filled thick SiO2 layer structure, the β-Ga2O3 Schottky Barrier Diode (SBD) demonstrates improved breakdown voltage and specific on-resistance, exceeding the performance of SiC and GaN. With state-of-the-art values of these performance metrics, the vertical β-Ga2O3 SBDs show great potential for high voltage and high power applications.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Yuangang Wang et al.
Summary: By implementing a composite terminal structure with a p-NiO junction termination extension and a small-angle beveled field plate, high-performance p-NiO/ss-Ga2O3 heterojunction diodes were successfully demonstrated. This structure significantly increases the breakdown voltage of ss-Ga2O3 and achieves low ON-resistance, making it a promising candidate for various applications.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Review
Materials Science, Coatings & Films
Luke A. M. Lyle
Summary: Over the past decade, there has been a growing interest in the utilization of beta-phase gallium oxide (beta-Ga2O3) for high-power electronics due to its wide bandgap and high breakdown field. Significant progress has been made in the development of beta-Ga2O3, particularly in the study of metal/beta-Ga2O3 interfaces. The research has shown promising results in terms of Schottky and Ohmic contacts, with low ideality factors and high barrier heights achieved. This comprehensive review focuses on the fundamental physics of electrical contacts to beta-Ga2O3, examining the influence of surface treatments and defects on Ohmic and Schottky contacts.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2022)
Article
Physics, Applied
Jian-Sian Li et al.
Summary: Vertical heterojunction NiO/beta n-Ga2O/n(+) Ga2O3 rectifiers with extended NiO layer beyond the rectifying contact exhibit high breakdown voltage and power figure-of-merit. Optimization of the design can reduce the peak electric field at the edge of the rectifying contact.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Xinyi Xia et al.
Summary: The band alignment of sputtered NiO on beta-Ga2O3 was measured using x-ray photoelectron spectroscopy for different annealing temperatures. The results showed that the band alignment is type II, with the magnitude of the conduction and valence band offsets increasing with annealing temperature. Additionally, the bandgap of NiO decreased with increasing annealing temperature.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Multidisciplinary Sciences
Jincheng Zhang et al.
Summary: In this study, Ga2O3 heterojunction PN diodes are demonstrated to overcome the challenges of high breakdown voltage and low doping, achieving high power figure-of-merit and showing great potential for next-generation power electronics applications.
NATURE COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Ming-Hsun Lee et al.
Summary: The effect of post-metallization anneal temperature on Ti/Au ohmic contact performance for (100)-oriented Ga2O3 was investigated. An optimal anneal temperature of around 420°C resulted in low contact resistance, but a drastic degradation occurred at 520°C with the formation of GaAu2 inclusions and an expanded Ti-TiOx interfacial layer at the degraded ohmic contact site. The findings emphasize the critical influence of Ga2O3 anisotropy on the optimal post-metallization anneal temperature and suggest the need for alternative metallization schemes for gallium oxide.
Proceedings Paper
Computer Science, Hardware & Architecture
Weibing Hao et al.
Summary: This study demonstrates an effective edge termination technique for vertical NiO/β-Ga2O3 heterojunction diodes, achieving high breakdown voltage and high-temperature voltage blocking capability in diodes with uniform leakage current distribution.
2022 IEEE 34TH INTERNATIONAL SYMPOSIUM ON POWER SEMICONDUCTOR DEVICES AND ICS (ISPSD)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
R. Kaplar et al.
Summary: This paper presents a study that aims to incorporate some important factors for Ultra-Wide-Bandgap semiconductors into more realistic Figures of Merit (FOM) calculations.
6TH IEEE ELECTRON DEVICES TECHNOLOGY AND MANUFACTURING CONFERENCE (EDTM 2022)
(2022)
Review
Engineering, Electrical & Electronic
Hardhyan Sheoran et al.
Summary: This study comprehensively reviews the recent development of metal-semiconductor contacts on ultrawide bandgap beta-gallium oxide (beta-Ga2O3). The study starts by introducing the basic concepts of metal-semiconductor contacts and then summarizes the current literature on ohmic and Schottky contacts on beta-Ga2O3. Finally, the status of high-power Schottky diode contact on beta-Ga2O3 is presented.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Physics, Applied
Jian-Sian Li et al.
Summary: Vertical heterojunction NiO/beta n-Ga2O/n(+) Ga2O3 rectifiers with NiO layer extension beyond the rectifying contact for edge termination show significantly improved breakdown voltages and power figure-of-merits compared to conventional rectifiers. Optimization of NiO doping and thickness design, as well as extension beyond the rectifying contact, can reduce the peak electric field at the edge of the rectifying contact.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
F. Zhou et al.
Summary: In this study, a large-area beveled-mesa p-NiO/beta-Ga2O3 bipolar heterojunction diode with advantageous characteristics such as low subthreshold slope, low resistance, high current density, and high breakdown voltage was demonstrated. The device also exhibited extreme switching capabilities and high temperature stability, making a significant step towards achieving high figure-of-merit in beta-Ga2O3 power devices.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Hehe Gong et al.
Summary: Ga2O3 power diodes are crucial in power electronics, and NiO/Ga2O3 p-n heterojunction diodes have demonstrated better performance and stability, with high breakdown voltage and transient current capability superior to past research results.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Review
Physics, Applied
Chenlu Wang et al.
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
Physics, Applied
Qinglong Yan et al.
Summary: This paper presents high-performance beta-Ga2O3 hetero-junction barrier Schottky (HJBS) diodes with p-type NiOx, achieving low on-resistance, high breakdown voltage, and a high DC figure of merit while minimizing reverse leakage current by shrinking the width of beta-Ga2O3. The incorporation of p-type NiOx enhances the sidewall depletion effect in beta-Ga2O3 HJBS diodes, making them an effective route for Ga2O3 power device technology with high PFOM and reduced reverse leakage current.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Applied
H. H. Gong et al.
Summary: This work demonstrates high-performance beta-Ga2O3 vertical heterojunction barrier Schottky diodes and investigates the reverse leakage mechanisms. Through experiments and simulations, it is found that the improved performance of the devices is attributed to the suppression of electric field crowding effect at device edges and the enhanced capability of sustaining high breakdown voltage by using alternative bipolar structures. This study provides important insights for achieving high-performance beta-Ga2O3 power devices.
APPLIED PHYSICS LETTERS
(2021)
Article
Crystallography
Hong Zhou et al.
Summary: This study comprehensively investigates and optimizes the implementation of p-NiO in beta-Ga2O3-based diodes through TCAD simulation, providing design guidelines for future Ga2O3 diodes. The findings suggest that adjusting the doping concentration and dimensions of p-NiO can significantly improve the breakdown voltage of the diode.
Article
Physics, Condensed Matter
Amit Kumar Singh et al.
Summary: Gallium oxide (Ga2O3) films were deposited using RF magnetron sputtering on quartz and n-type Si (100) substrates at room temperature, and the effect of annealing temperature on the crystalline structure and band gap of beta-Ga2O3 thin films was investigated. Monoclinic polycrystalline thin films were formed, with a bandgap estimated in the range of 4.75 eV-5.15 eV. Raman spectra showed shifts in Ga2O3 phonon modes, and absorption bands at 647.05 cm(-1) due to vibrations of Ga-O bonds were identified through Fourier-transform infrared spectroscopy.
SUPERLATTICES AND MICROSTRUCTURES
(2021)
Article
Physics, Applied
H. H. Gong et al.
APPLIED PHYSICS LETTERS
(2020)
Article
Engineering, Electrical & Electronic
Shivam Sharma et al.
IEEE ELECTRON DEVICE LETTERS
(2020)
Article
Nanoscience & Nanotechnology
J. E. N. Swallow et al.
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Physics, Applied
S. J. Pearton et al.
JOURNAL OF APPLIED PHYSICS
(2018)
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Physics, Applied
Yoshihiro Kokubun et al.
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