First Demonstration of 500 °C Operation of β-Ga2O3 MOSFET in Air

Abstract

β-Ga2O3 offers a robust platform for operation of electronic devices at high temperature and in extreme environments due to its large band gap of ~4.8 eV and low intrinsic carrier concentration. In this study, we characterize β-Ga2O3 field effect transistors from room temperature (RT) up to 500 °C. The devices, fabricated with Ni/Au gate metal and Al2O3 gate dielectric, exhibited stable operation up to 500 °C. The measured ID-VD characteristics showed no current degradation up to 450 °C; in fact, current improved in this temperature range due to activation carriers from dopants/traps in the device. At 500 °C, device exhibited a drop in ID; however, device characteristics are recovered once the device is brought back to RT even after 20 hours of device operation at 500 °C. All other device characteristics (gate leakage, ION/IOFF ratio, gm, Ron, contact resistance) showed monotonic variation with temperature, which has been explained using appropriate device physics and by considering the interaction of gate metals with Al2O3. Our results suggest that with appropriate choice of metals and gate dielectrics the 500 °C operation using β-Ga2O3 has no bottlenecks.