Transient pulsed analysis on GaN HEMTs at cryogenic temperatures

A pulsed measurement of AlGaN/GaN high electron mobility transistors (HEMTs) current-voltage (I-V) output characteristics from 100 to 300 K temperatures has been systematically investigated, and a significant kink is clearly observed, which is more severe at cryogenic temperatures. By comparing the pulsed and dc I-V curves, the kink effect is more significant in the pulsed mode evaluation, which indicates a time constant related mechanism involved in the carrier transport. Moreover, a weak impact ionization by monitoring the gate current in the on-state of device has also been observed, and it is more significant at cryogenic temperatures.