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

β-Ga
2
O
3
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-Ga
2
O
3
field effect transistors from room temperature (RT) up to 500 °C. The devices, fabricated with Ni/Au gate metal and Al
2
O
3
gate dielectric, exhibited stable operation up to 500 °C. The measured I
D
-V
D
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 I
D
; 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, I
ON
/I
OFF
ratio, g
m
, R
on
, contact resistance) showed monotonic variation with temperature, which has been explained using appropriate device physics and by considering the interaction of gate metals with Al
2
O
3
. Our results suggest that with appropriate choice of metals and gate dielectrics the 500 °C operation using β-Ga
2
O
3
has no bottlenecks.