HOME > Profile > OSHIMA, Takayoshi
Research
PublicationsNIMS affiliated publications since 2004.
Society memberships
応用物理学会
Research Center for Electronic and Optical Materials
Studies on oxide power semiconductors
power semiconductor, Ga2O3, GeO2
Overview
In the semiconductor field, there is a growing demand for the commercialization of ultralow-loss power devices based on next-generation power semiconductors. Among these materials, Ga2O3 and GeO2, which have relatively short histories of research and development, have recently attracted considerable attention because of their fundamental material properties that offer advantages for power device applications over more established semiconductors such as silicon carbide and gallium nitride. In this research, we aim to develop device applications of these emerging oxide power semiconductors through collaborative research, covering a broad range of topics from the evaluation of fundamental material properties to the development of device technologies.
Novelty and originality
For example, we have proposed a new substrate orientation, (−112), for β-phase gallium oxide (β-Ga2O3) semiconductors and are exploring its potential.
Details
As an example of our research, we introduce homoepitaxial growth and gas etching of (−112) β-Ga2O3. Although this orientation corresponds to one of the principal oxygen lattice planes of β-Ga2O3, it has received little attention until recently. We therefore prepared (−112) β-Ga2O3 substrates and performed homoepitaxial growth by halide vapor phase epitaxy (HVPE). As shown in the figure, ideal single-crystal step-flow growth was achieved, resulting in a smoother surface than those previously reported for other substrate orientations. Furthermore, HCl gas etching enabled vertical etching with (100) sidewalls and minimal lateral etching, reflecting the crystallographic anisotropy of β-Ga2O3. These achievements contribute to the advancement of crystal growth and microfabrication technologies essential for power device development. We are continuing to explore the further potential of the (−112) orientation of β-Ga2O3.
[Reference] T. Oshima, and Y. Oshima, Sci. Technol. Adv. Mater. 27, 2680969 (2026).
Summary
In this way, we are conducting a broad range of research and development on oxide power semiconductors, from fundamental research to device applications, by introducing novel ideas from new perspectives.
