The Applied Science of Gallium Oxide: Lessons, Challenges and Goals

Gallium oxide (β-Ga₂O₃) is an emerging ultra-wide band gap semiconductor which shows promise across a range of applications due to its high critical breakdown field, readily available n-type dopant species, and low native substrate cost. The Air Force Research Laboratory is particularly interested in β-Ga₂O₃ for applications including high-frequency converter operation, power switching, and on-chip power conversion, all of which serve to improve the size, weight, power, and cost of sensors systems. Realizing the potential of β-Ga₂O₃ in prototype devices has necessitated clever solutions to challenging problems in materials science and materials engineering. In this talk, we will discuss some of the materials science and engineering challenges β-Ga₂O₃has faced, as well as the solutions that have been implemented. We will discuss the identification and mitigation of Si contamination sources in β-Ga₂O₃ epitaxy, optimizing regrowth and liftoff for ohmic contact formation, defect engineering of the oxide-semiconductor interface in β-Ga₂O₃MOSFETs, and challenges in device design for high-temperature applications. We will also discuss open challenges in β-Ga₂O₃ that may have solutions in future materials science research.