(Invited) Ga₂O₃ Semiconductor Devices for High-Temperature Operation

Abstract

Beta phase of gallium oxide (Ga 2 O 3 ) has attracted a lot of attention as an ultra-wide band gap semiconductor for applications in high-power electronic devices. High power operation often comes with increased temperatures of the devices due to joule heating, especially in semiconductors like Ga 2 O 3 with low thermal conductivity. However, electrical performance and reliability of the Ga 2 O 3 based diodes and transistors at very high temperature, above 400C, is not well established. In this talk, I will present our recent experimental results on fabrication of Ga 2 O 3 semiconductor devices for applications as high-temperature diodes and hydrogen gas sensors. The fabricated Ga 2 O 3 /NiO p-n heterojunctions allow for device operation with >100-1000 rectification ratio up to 400-600C [1]. Despite the stable ultrathin Ohmic contact [2], the device performance degrades over tens of temperature cycles and hundreds of hours at these elevated temperatures, likely due to instability of the rectifying contact. We propose and implement alternative interfacial rectifying contact layers, that enable both high performance and long reliability of these high temperature Ga 2 O 3 semiconductor devices. [1] Sohel, Zakutayev et al Physica Status Solidi (a) 220 2300535 (2023) [2] Callahan, Zakutayev et al J. Vac. Sci. Technol. A 41, 043211 (2023)