The Diverse Landscape of Gallium Oxide Power Electronics

More than ten years has passed since the inception of gallium oxide (Ga2O3) power electronics by Higashiwaki and co-workers. There has been intense focus on Ga2O3 power device development that capitalizes on melt-grown native substrates, with 4-inch wafers already commercially available and 6-inch wafers on the horizon, indicating a path to a commercially viable technology. These research efforts have been driven in large part by a need for new medium/high-voltage power devices that meet stringent requirements for system size and cost in emerging areas such as electrified transportation, motor-drive systems, and renewable energy integration with the grid. As an ultrawide-bandgap (4.8 eV) semiconductor with high breakdown field, Ga2O3 is expected to enable new performance levels for those applications, but the full potential of Ga2O3 power switching technology is still far from being exploited. To commemorate a decade of Ga2O3 research, I will reflect on the demonstrated benefits as well as unrealized potentials of emerging β-Ga2O3 devices, whose performance has been limited by various factors such as nonoptimal electric-field shaping and self-heating. Specifically, I will describe design considerations of both lateral and vertical power transistor structures, field management techniques, process challenges, and theoretical developments of relevant physics, then conclude with my views on how the landscape of Ga2O3 electronics may evolve going forward.