Gallium Oxide Heterojunction Diodes for 400 degree C High-Temperature Applications: Article No. 2300535

..beta..-Ga2O3-based semiconductor devices are expected to have significantly improved high-power and high-temperature performance due to its ultrawide bandgap of close to 5 eV. However, the high-temperature operation of these ultrawide-bandgap devices is usually limited by the relatively low 1-2 eV built-in potential at the Schottky barrier with most high-work-function metals. Herein, heterojunction p-NiO/n-..beta..-Ga2O3 diodes fabrication and optimization for high-temperature device applications are reported, demonstrating a current rectification ratio (ION/IOFF) of more than 106 at 410 degrees C. The NiO heterojunction diode can achieve higher turn-on (VON) voltage and lower reverse leakage current compared to the Ni-based Schottky diode fabricated on the same single-crystal ..beta..-Ga2O3 substrate, despite charge transport dominated by interfacial recombination. Electrical characterization and device modeling show that these advantages are due to a higher built-in potential and additional band offset. These results suggest that heterojunction p-n diodes based on ..beta..-Ga2O3 can significantly improve high-temperature electronic device and sensor performance.