Ultrawide Bandgap β-Ga₂O₃ Transistors for Efficient Multi-Kilovolt Power Switching (Invited)

Abstract

β-Ga 2 O 3 has emerged as a material that demonstrates numerous strengths for next-generation high voltage/power applications. Its projected material power figure of merit (PFOM) is almost 3500×, 10×, and 4× higher than that of Silicon, SiC, and bulk GaN. In this work, state-of-the-art electron mobilities, contact resistance values, breakdown voltages, and power figures of merit are demonstrated in β-Ga 2 O 3 epitaxial films and power devices. Record low specific contact resistance (pc) and total contact resistance (Rc) of 1.62 × 10– ⁷ Ω.cm ² and 0.023 Ω.mm were realized for β-Ga 2 O 3 : Si films with n > 3 × 10 ²⁰ cm ^-3 . A low-temperature un-doped buffer-channel stack design is developed, which demonstrates record high Hall (up to 196 cm ² /Vs) and drift electron mobilities (up to 125 cm ² /Vs) in doped β-Ga 2 O 3 channels allowing for low ON resistances (R ON ) in β-Ga 2 O 3 MESFETs with record high PFOM close to ~ 1GW/cm ² . 4.4 kV class β-Ga 2 O 3 lateral MESFETs surpassing theoretical UFOM of Silicon are also realized.