Gallium Oxide Advances Pave the Way for Next-Generation Power Electronics

Researchers at Nagoya University in Japan, collaborating with spinout company NU-Rei Co., Ltd., have announced six significant advancements in the development of gallium oxide (Ga₂O₃) thin-film growth. These breakthroughs, presented at the spring meeting of the Japan Society of Applied Physics (March 15-18, 2026), aim to accelerate the adoption of this promising semiconductor material for high-voltage, high-frequency, and silicon-integrated device applications, particularly in electric vehicles, power conversion systems, and space applications.

Why Gallium Oxide?

Gallium oxide is gaining traction in the power semiconductor industry due to its potential to create devices that can handle higher voltages using relatively abundant and lower-cost raw materials compared to other wide-bandgap semiconductors like silicon carbide and gallium nitride. Nagoya University reports that the material offers a compelling combination of performance and cost-effectiveness.

Key Advances in Gallium Oxide Growth

The research group’s advancements address critical aspects of the gallium oxide manufacturing process, bringing the technology closer to commercial viability. These include:

• High-Density Oxygen Radical Source (HD-ORS): A newly developed HD-ORS doubles the density of atomic oxygen during thin-film growth, enhancing the chemical reaction converting gallium suboxide into Ga₂O₃ and increasing film growth speed. This source is compatible with both molecular beam epitaxy (MBE) and physical vapor deposition (PVD) techniques.
• High-Speed MBE Homoepitaxial Growth: Utilizing the HD-ORS, the team achieved a growth rate of 1 µm per hour at 300°C on tin-doped Ga₂O₃ substrates.
• High-Speed PVD Homoepitaxial Growth: Applying HD-ORS to PVD resulted in stable film growth rates exceeding 1 µm per hour, approaching ten times the rate of conventional MBE.
• Silicon Substrate Pretreatment: A novel pretreatment process combining wet chemical cleaning with controlled gallium adsorption prevents re-oxidation during heating, crucial for successful heteroepitaxial growth.
• World-First Heteroepitaxial Growth on Silicon: The team successfully grew Ga₂O₃ on two-inch silicon (Si(100)) wafers, a significant step towards reducing device costs and improving heat dissipation. Silicon substrates are less expensive than native Ga₂O₃ substrates and offer superior thermal conductivity.
• p-type Formation via NiO Diffusion Layers: Researchers formed a graded nickel oxide (NiO) diffusion layer with p-type characteristics using nickel ion implantation and annealing, demonstrating pn junction behavior on both Ga₂O₃ and GaN substrates.

Building on Previous Successes

These latest results build upon prior work by Nagoya University, including an advance in gallium oxide p-type control reported in September 2025. NU-Rei Co., Ltd. Is actively commercializing these advancements to support industrial adoption of gallium oxide growth processes.

Commercialization Efforts

NU-Rei Co., Ltd., a spin-off from Nagoya University, is focused on bringing these technologies to market. The company aims to support the industrial adoption of gallium oxide for high-voltage, high-frequency, and silicon-integrated device applications.

Looking Ahead

The advancements presented by Nagoya University and NU-Rei Co., Ltd. Represent a significant step forward in the development of gallium oxide as a viable alternative to existing power semiconductors. Continued innovation in materials science and manufacturing techniques will be crucial to unlocking the full potential of this promising technology and enabling its widespread adoption across various industries.