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

β-Ga2O3 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-Ga2O3 epitaxial films and power devices. Record low specific contact resistance (pc) and total contact resistance (Rc) of 1.62 × 10–⁷Ω.cm²and 0.023 Ω.mm were realized for β-Ga2O3: Si films with n > 3 × 10²⁰cm^-3. A low-temperature un-doped buffer-channel stack design is developed, which demonstrates record high Hall (up to 196 cm²/Vs) and drift electron mobilities (up to 125 cm²/Vs) in doped β-Ga2O3 channels allowing for low ON resistances (RON) in β-Ga2O3 MESFETs with record high PFOM close to ~ 1GW/cm². 4.4 kV class β-Ga2O3 lateral MESFETs surpassing theoretical UFOM of Silicon are also realized.