Query: Crystal growth of gallium oxide based wide bandgap semiconductors

Candidate papers:

author_names: Qixin Guo Katsuhiko Saito Tooru Tanaka

Mitsuhiro Nishio
title: Crystal growth of gallium oxide based wide bandgap semiconductors
year: 2016

abstract: Gallium oxide is not a novel material, but has been overlooked in favor of semiconductors like gallium nitride and silicon carbide. It is a typical ultra wide bandgap material and has attractive material properties represented by its extremely large bandgap of 4.85 eV. Recent revolution in its bulk single crystal growth methods has inspired scientist to research more on this material. Though the research on the material has picked up, there is still a lot of ground to cover to catch up to standard commercialized semiconductors. TCAD's have inspired their own line of research based on the understanding of device physics, and most TCADs are tailored to standard semiconductors. In this thesis we address one such device physics required to determine the breakdown voltage of gallium oxide devices, the physics of impact ionization. We use known physical properties of gallium oxide in standard models to obtain an estimate of the ionization coefficients. We also determine certain properties, essential for the estimation of the coefficients, based on approximation models. The estimates are compared with GaN and SiC and is found to be higher in gallium oxide as expected.
author_names: Giftsondass Irudayadass
title: Estimation of Ionization Coefficients of Gallium Oxide for the Purpose of TCAD Simulation
year: 2018

abstract: Zinc oxide (ZnO) and gallium nitride (GaN) are wide bandgap semiconductors with a wide array of applications in optoelectronic and electronics. The lack of low cost, low defect ZnO and GaN substrates has slowed development and hampered performance of devices based on these two materials. Their anisotropic crystal structure allows the polar solvents, water and ammonia, to dissolve and crystallize ZnO and GaN at high pressure. Applying the techniques used for hydrothermal production of industrial single crystal quartz to ZnO and GaN opens a pathway for the inexpensive growth of relatively larger crystals that can be processed into semiconductor wafers. This chapter will focus on the specifics of the hydrothermal growth of ZnO and the ammonothermal growth of GaN, emphasizing requirements for industrial scale growth of large crystals. Phase stability and solubility of hydrothermal ZnO and ammonothermal GaN is covered. Modeling of thermal and fluid flow gradients is discussed and simulations of thermal and temperature profiles in research grade pressure systems are shown. Growth kinetics for ZnO and GaN respectively are reviewed with special interest in the effects of crystalline anisotropy on thermodynamics and kinetics. Finally, the incorporation of dopants and impurities in ZnO and GaN and how their incorporation modifies electrical and optical properties are discussed.
author_names: Michael J Callahan

Qi-sheng Chen
title: Hydrothermal and Ammonothermal Growth of ZnO and GaN
year: 2010

abstract: Historically, the exploration of III V compound semiconductors has begun with small bandgap materials and proceeded to large bandgap ones in recent years, that is, from GaAs based compounds to GaN based ones. We consider that gallium oxide (Ga2O3) is no exception in following this history and is poised to become the next mainstream of compound semiconductor research due to its attractive material properties based on an extremely large bandgap of about 4.5 eV [1] This bandgap energy is not only much larger than those of representative wide bandgap semiconductors such as GaN and SiC but also unique among single crystal semiconductors. Furthermore, Ga2O3 has another important advantage for commercialization over the other wide bandgap materials in that large size, high quality bulk single crystals can be synthesized by melt growth methods, thus allowing native substrates to be produced at a relatively low cost [2] Recently, these two features have drawn much attention to Ga2O3, resulting in a rapid expansion of the Ga2O3 community.
author_names: Masataka Higashiwaki

Man Hoi Wong

Takafumi Kamimura

Yoshiaki Nakata

Chia-Hung Lin

R Lingaparthi

Akinori Takeyama

Takahiro Makino

Takeshi Ohshima

Naoki Hatta

Kuniaki Yagi

Ken Goto

Kohei Sasaki

Shinya Watanabe

Akito Kuramata

Shigenobu Yamakoshi

Keita Konishi

Hisashi Murakami

Yoshinao Kumagai
title: Recent Advances in Ga2O3 MOSFET Technologies
venue: 2018 76th Device Research Conference (DRC)
year: 2018

abstract: Solar blind photodetectors are of great interest to a wide range of industrial, civil, environmental, and biological applications. As one of the emerging ultrawide bandgap semiconductors, gallium oxide (Ga2O3) exhibits unique advantages over other wide bandgap semiconductors, especially in developing high performance solar blind photodetectors. This paper comprehensively reviews the latest progresses of solar blind photodetectors based on Ga2O3 materials in various forms of bulk single crystal, epitaxial films, nanostructures, and their ternary alloys. The basic working principles of photodetectors and the fundamental properties and synthesis of Ga2O3, as well as device processing developments, have been briefly summarized. A special focus is to address the physical mechanism for commonly observed huge photoconductive gains. Benefitting from the rapid development in material epitaxy and device processes, Ga2O3 based solar blind detectors represent to date one of the most prospective solutions for UV detection technology towards versatile applications.
author_names: Xuanhu Chen

Fangfang Ren

Shulin Gu

Jiandong Ye
title: Review of gallium oxide based solar blind ultraviolet photodetectors
venue: Photonics Research
year: 2019

abstract: Beta gallium oxide (Ga2O3) has received much attention recently as a viable candidate for the nextgeneration material for power electronics and photonic applications, with its unique advantages, such as the wide bandgap 4.9 eV) high breakdown voltage, and optical transparency up to UV range. Recent advances in high quality Ga2O3 thin film growth, such as using molecular beam epitaxy or chemical vapor deposition, combined with the material's availability as inexpensive bulk substrates have opened new exciting opportunities for the fabrication of novel Ga2O3 devices. Despite the advances, many of the fundamental properties of Ga2O3 are yet to be understood clearly. As in many other oxide based transparent semiconductors, point defects and their complexes can dictate the properties of Ga2O3. Various spectroscopic methods as well as theoretical calculations have provided useful insights on the nature of the point defects and complexes in Ga2O3. Regardless, what has been missing in the field is the detailed information on the atomic scale structure of the defects and complexes in Ga2O3. Such information is crucial to determine how the atomic scale defects relate to many of the unanswered questions regarding the unique properties of Ga2O3, including how point defects and impurity atoms influence the formation of trap states, how the dopant atoms are compensated, and what is the exact origin of the difficulty in doping of Ga2O3 (especially p type)
author_names: Jared M Johnson

Hsien-Lien Huang

Jinwoo Hwang
title: Point Defects and Complexes in Gallium Oxide Materials and Devices
venue: Microscopy and Microanalysis
year: 2020

abstract: As a promising ultra wide bandgap semiconductor, gallium oxide (Ga2O3) has attracted increasing attention in recent years. The high theoretical breakdown electrical field (8 MV/cm) ultra wide bandgap 4.8 eV) and large Baliga's figure of merit (BFOM) of Ga2O3 make it a potential candidate material for next generation high power electronics, including diode and field effect transistor (FET) In this paper, we introduce the basic physical properties of Ga2O3 single crystal, and review the recent research process of Ga2O3 based field effect transistors. Furthermore, various structures of FETs have been summarized and compared, and the potential of Ga2O3 is preliminary revealed. Finally, the prospect of the Ga2O3 based FET for power electronics application is analyzed.
author_names: Hang Dong

Huiwen Xue

Qiming He

Yuan Qin

Guangzhong Jian

Shibing Long

Ming Liu
title: Progress of power field effect transistor based on ultra wide bandgap Ga2O3 semiconductor material
year: 2019

abstract: Abstract In the course of development of transparent semiconducting oxides (TSOs) we compare the growth and basic physical properties bulk single crystals of ultra wide bandgap (UWBG) TSOs, namely b Ga2O3 and Ga based spinels MgGa2O4, ZnGa2O4, and Zn1 xMgxGa2O4. High melting points of the materials of about 1800 1930 degC and their thermal instability, including incongruent decomposition of Ga based spinels, require additional tools to obtain large crystal volume of high structural quality that can be used for electronic and optoelectronic devices. Bulk b Ga2O3 single crystals were grown by the Czochralski method with a diameter up to 2 inch, while the Ga based spinel single crystals either by the Czochralski, Kyropoulos like, or vertical gradient freeze Bridgman methods with a volume of several to over a dozen cm3. The UWBG TSOs discussed here have optical bandgaps of about 4.6 5 eV and great transparency in the UV visible spectrum. The materials can be obtained as electrical insulators, n type semiconductors, or n type degenerate semiconductors. The free electron concentration (ne) of bulk b Ga2O3 crystals can be tuned within three orders of magnitude 1016 1019 cm 3 with a maximum Hall electron mobility (m) of 160 cm2V 1s 1, that gradually decreases with ne. In the case of the bulk Ga based spinel crystals with no intentional doping, the maximum of ne and m increase with decreasing the Mg content in the compound and reach values of about 1020 cm 3 and about 100 cm2V 1s 1 (at ne 1019 cm 3) respectively, for pure ZnGa2O4.
author_names: Zbigniew Galazka

Steffen Ganschow

Klaus Irmscher

Detlef Klimm

Martin Albrecht

Robert Schewski

Mike Pietsch

T Schulz

Andrea Dittmar

Albert Kwasniewski

Raimund Grueneberg

Saud Bin Anooz

Andreas Popp

Uta Juda

Isabelle M Hanke

Thomas Schroeder

Matthias Bickermann
title: Bulk single crystals of b Ga2O3 and Ga based spinels as ultra wide bandgap transparent semiconducting oxides
year: 2021

abstract: Gallium oxide (Ga2O3) possesses excellent material properties especially for power device applications. It is also attractive from an industrial viewpoint since large size, high quality wafers can be manufactured by using simple methods. These two features have drawn much attention to Ga2O3 as a new wide bandgap semiconductor following SiC and GaN. In this report, we describe the recent progress in development on fundamental technologies for Ga2O3 devices, covering wafer production from melt grown bulk single crystals, homoepitaxial thin film growth by halide vapor phase epitaxy, as well as device processing and characterization of metal oxide semiconductor field effect transistors and Schottky barrier diodes.
author_names: Masataka Higashiwaki

Kohei Sasaki

Man Hoi Wong

Takafumi Kamimura

Ken Goto

Kazushiro Nomura

Quang Tu Thieu

Rie Togashi

Hisashi Murakami

Yoshinao Kumagai

Bo Monemar

Akinori Koukitu

Akito Kuramata

Takekazu Masui

Shigenobu Yamakoshi
title: Current Status of Gallium Oxide Based Power Device Technology
venue: 2015 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS)
year: 2015

abstract: This article lists the development history and application prospect of the third generation of semiconductor material wide bandgap zinc oxide single crystal,and summarizes the structural performance,application direction and preparation technique of ZnO.The article also introduces the distinct advantages of wide bandgap zinc oxide single crystal compared to gallium nitride which are as follow:more powerful exciton binding energy(60 mev),lower lasing threshold,very likely to achieve ultraviolet laser of high efficiency and low threshold under indoor temperature.Compared to the very successful gallium nitride,the cost of the raw material for ZnO is extremely low and it is environmental friendly and easy for synthesis.For the moment,the difficult and hot issues of the research on ZnO semiconductor material focus on the research and development of p type doping materials and devices.Excellent physical properties of zinc oxide have made it a new generation of mainstream broadband gap semiconductor materials.Growth of zinc oxide single crystal of large size and high crystallization quality has a great significance for both of basic research and practical application.The method and techical advantage of hydrothermal synthesis of wide bandgap zinc oxide single crystal have been specially introduced in this article which demonstrates our latest research development of hydrothermal synthesis of wide bandgap zinc oxide single crystal.
author_names: Wang Jin-lian
title: Research Progress on Hydrothermal Growth of Wide Bandgap ZnO Single Crystal
year: 2015