Hot Carrier Stress Effects of SiO2 Passivated AlGaN/GaN High Electron Mobility Transistors

Abstract

The hot carrier stress with VDS=10 V, VGS=0 V and 5×104 sec is applied to AlGaN/GaN HEMTs before and after SiO2 passivation. The measured forward drain current of AlGaN/GaN HEMTs before and after SiO2 passivation decreases by 4.62 % and 5.46 % after the hot carrier stress. The SiO2 passivation suppresses the electron trapping in surface states so that the degradation due to the hot carrier stress is decreased. The threshold voltage is shifted to a positive direction after the hot carrier stress. The threshold voltage of SiO2 passivated and unpassivated AlGaN/GaN HEMTs after the hot carrier stress increases by 0.14 V and 0.22 V respectively. The leakage current of both devices decreases after the hot carrier stress due to the increased depletion.