Electrical Degradation of In Situ SiN/AlGaN/GaN MIS-HEMTs Caused by Dehydrogenation and Trap Effect Under Hot Carrier Stress

The gate and drain bias dependence of hot electron-induced degradation in GaN-based metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) was investigated in this work. Devices exhibit an abnormal increase in peak transconductance ( G
_m
,max) during hot carrier stress (HCS) and a partially quick recovery of that after removing the electrical stress. A physical model is proposed to explain the abnormal electrical characteristics caused by HCS. By using density functional theory (DFT), we calculated the energy for electrons to dehydrogenate preexisting [N
_Ga
H
₃
]
^-1
complexes in GaN layer during stress. The dehydrogenation of defects affects the G
_m,max
of devices. Meanwhile, the neutralization of donor traps in AlGaN barrier layer also plays a significant role in the increase of G
_m,max
and the detrapping effect of electrons from these traps after removing the electrical stress accounts for the partially quick recovery of G
_{m, max}
.