Drain bias dependence of Y22 and Y21 signals at low frequency for on-state conditions in AlGaN/GaN HEMTs

Drain bias dependence of Y22 and Y21 signals has been investigated by two-port network measurement at the on-state condition of AlGaN/GaN high electron mobility transistors (HEMTs). Y22 has signals for Fe-related trap in GaN layers and self-heating effect. Y21 has a unique signal otherwise than the signals with the same drain bias dependence as Y22 signals.　 This unique signal is considered to originate from the AlGaN trap using the device simulation with the GaN trap, AlGaN trap, and self-heating effect. The peak frequency of GaN and AlGaN traps increases as increasing the drain voltages, while the peak frequency of the self-heating doesn’t depend on the drain voltages.