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

The drain bias dependence of Y-22 and Y-21 signals has been investigated by two-port network measurement in the on-state condition of AlGaN/GaN high electron mobility transistors. Y-22 has signals for Fe-related traps in GaN layers and the self-heating effect. The Y-21 signal is unique among signals with the same drain bias dependence as Y-22 signals. This unique signal is considered to originate from AlGaN traps, using device simulation with a GaN trap, AlGaN trap and the self-heating effect. The peak frequency of GaN and AlGaN traps increases with increasing drain voltage, while the peak frequency of self-heating does not depend on the drain voltage.