Experimental Study of Heavy Ion Irradiation Hardness for p-GaN HEMTs Under Off-State With Negative Gate Voltage

In this work, it is demonstrated for the first time that a negative gate voltage ( ${V} _{\text {GS}}$ ) during off-state can enhance the single-event effect (SEE) hardness of the 100-V E-mode p-GaN HEMTs. When subjected to irradiation from Ta ions with linear energy transfer of 78.40 MeV/(mg/cm2), the single-event transient (SET) current peak during irradiation can be significantly decreased if a negative ${V} _{\text {GS}}$ is applied, as opposed to using zero ${V} _{\text {GS}}$ . Furthermore, a negative ${V} _{\text {GS}}$ suppresses post-irradiation shifts in gate capacitance ( ${C} _{\text {G}}$ ), threshold voltage ( ${V} _{\text {th}}$ ) and off-state drain leakage current ( ${I} _{\text {DSS}}$ ), indicating improved stability against SEE. Numerical simulations have been performed to offer a physical insight into the underlying mechanisms. It is found that a negative ${V} _{\textit {GS}}$ enables the simultaneous removal for radiation-induced holes and thus suppresses the SET current. The post-irradiation degradation of ${C} _{G}$ , ${V} _{\text {th}}$ and ${I} _{\text {DSS}}$ are attributed to the radiation-induced acceptor-like traps at the Schottky junction, the AlGaN/GaN interface and the buffer layer, respectively.