Small-signal and DC characterization of stressed GaN-on-Si HEMTs

Shifts in GaN-on-Si HEMT device characteristics due to the combined effects of high electrical field stress, thermal stress, and electron trapping are reported. A stressing experiment is carried out to analyze the effects of high symmetrical electric field distributions upon device degradation for four groups of commercial GaN-on-Si devices. Characterization of degradation involved analyzing I-V characteristics, transfer characteristics, and S-parameters before and after stressing. Results from these experiments show an expected increase in gate leakage, but also return an increase in saturation drain current, a negative shift in threshold voltage, and a decrease in reverse transmission gain and associated small signal gate-to-drain capacitance after stressing under a symmetrical electric field distribution.