Researchers in Japan are reporting significant breakthroughs in the development of gallium oxide (Ga₂O₃), a semiconductor material poised to revolutionize power electronics. These advancements, presented at the spring meeting of the Japan Society of Applied Physics (March 15–18, 2026), address key challenges in manufacturing and scalability, bringing the material closer to widespread use in applications ranging from electric vehicles to power grids.
Gallium oxide has garnered increasing attention within the power semiconductor industry due to its potential to create devices capable of handling higher voltages with more readily available and cost-effective raw materials compared to existing technologies like silicon carbide and gallium nitride. The research, a collaboration between Nagoya University and its spinout company NU-Rei Co., Ltd., focuses on improving the growth processes of Ga₂O₃, aiming for more efficient and affordable production. This work builds on previous progress in controlling the p-type doping of gallium oxide, reported by Nagoya University in September 2025, and is being actively commercialized by NU-Rei Co., Ltd.
At the core of these advancements is a newly developed High-Density Oxygen Radical Source (HD-ORS). According to researchers, this source doubles the density of atomic oxygen during thin-film growth, significantly boosting the chemical reaction that forms the desired Ga₂O₃ compound while minimizing unwanted byproducts. The HD-ORS is compatible with both molecular beam epitaxy (MBE) and physical vapor deposition (PVD), offering flexibility for different production scales.
Crystal structure of gamma gallium oxide. Credit: Wikimedia Commons. Image generated using CrystalMaker: a crystal and molecular structures program for Mac and Windows. CrystalMaker Software Ltd, Oxford, England (www.crystalmaker.com). Creative Commons Attribution-Share Alike 4.0 International license.
Key Advances in Gallium Oxide Growth
The research team detailed six key results, collectively addressing the entire manufacturing process. These include achieving high-speed homoepitaxial growth using both MBE and PVD techniques. Using the HD-ORS, they achieved a growth rate of 1 µm per hour for β-Ga₂O₃ on tin-doped substrates at 300°C. PVD, utilizing the new oxygen source, demonstrated even faster growth rates, approaching ten times that of conventional MBE, potentially enabling industrial-scale production.
A significant hurdle in gallium oxide development has been the difficulty in growing high-quality crystals on silicon substrates, which are cheaper and offer better heat dissipation than native Ga₂O₃ substrates. Researchers successfully achieved a “world-first” heteroepitaxial growth of Ga₂O₃ on two-inch silicon wafers. This was accomplished through a pretreatment process involving wet chemical cleaning and the controlled deposition of a single atomic layer of gallium onto the silicon surface, preventing re-oxidation during heating.
the team made progress in creating p-type gallium oxide, essential for building the pn junctions that form the basis of power devices. They utilized nickel ion implantation and annealing to form a graded nickel oxide (NiO) diffusion layer with p-type characteristics, demonstrating improved current density compared to standard nickel Schottky diodes on both Ga₂O₃ and gallium nitride (GaN) substrates.
Implications for Power Electronics
These advancements address critical limitations in gallium oxide technology, potentially unlocking its full potential in a range of applications. The ability to grow Ga₂O₃ on silicon substrates could significantly reduce manufacturing costs, while the improved growth rates and p-type doping techniques pave the way for more efficient and powerful devices. As noted by Nagoya University, these developments are geared towards supporting the industrial adoption of gallium oxide for high-voltage, high-frequency, and silicon-integrated applications.
The ongoing research and commercialization efforts surrounding gallium oxide are occurring within a broader context of increasing demand for efficient power electronics. The transition to electric vehicles, the expansion of renewable energy sources, and the growing need for robust power conversion systems are all driving the search for materials that can outperform existing semiconductors. Gallium oxide, with its unique properties, is emerging as a strong contender in this field.
Looking ahead, the focus will likely be on refining these growth techniques, improving device performance, and scaling up production to meet anticipated demand. The results presented at the Japan Society of Applied Physics meeting represent a crucial step towards realizing the full potential of gallium oxide as a next-generation power semiconductor.
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