High temperature operation of Beta-Ga2O3 transistors

We studied the application of Beta-Ga2O3 for high temperature operation up to 500C. Field effect transistors were fabricated using epitaxial films grown on insulating Beta-Ga2O3 substrates. Variable temperature DC measurements were performed in vacuum and air ambient. Measurements revealed a reduction in on/off ratio for the devices due to increase in thermionic emission over the gate/dielectric barrier of MOSFET and over the gate/semiconductor barrier of MESFET. Devices also exhibited detrapping of electrons from interface traps with the increase in temperature. After the devices were tested intermittently at different high temperatures in vacuum or in air ambient, suggesting no change in semiconductor and contact properties.