Thermal Assessment of AlGaN/GaN MOS-HEMTs on Si Substrate Using Gd2O3 as Gate Dielectric

Thermal stability of AlGaN/GaN metal–oxide–semiconductor high-electron mobility transistors (MOS-HEMTs) and diodes using Gd
₂
O
₃
is investigated by means of different thermal tests. DC and pulsed
$I$
–
$V$
characterization of the devices before and after the processes shows that the devices with Gd
₂
O
₃
dielectric layer have more than three orders of magnitude lower leakage current, higher ON/OFF ratio of about
$10^{8}$
, and better thermal stability after the long thermal storage test (500 °C, 8 days) compared with conventional devices. In addition, no hysteresis and a stable threshold voltage were observed after a short thermal test (500 °C, 5 min) in the MOS diodes, in good agreement with the lower trapping effects observed in the MOS-HEMTs.