Recoverable Current Collapse Effect of p-GaN HEMTs Under Short Circuit Stress

This study investigates the recoverable current collapse phenomenon of p-GaN devices under repetitive short-circuit (SC) stress. A SC platform is established to simulate high-voltage and high-current conditions. The degradation of threshold voltage, saturation current, and conduction resistance indicates the occurrence of current collapse due to SC stress. Both gate and drain leakage decrease under SC stress, but these DC parameters recover after a 2-day period, suggesting that the current collapse under SC stress is caused by the charging and discharging of defects. Moreover, after 1000 cycles of SC stress, the bias temperature instability (BTI) is intensified, and this is accompanied by a decrease in gate leakage current, which, in turn, indicates a reduction in hole injection from the gate metal. The underlying mechanism involves the capture of channel electrons by AlGaN, p-GaN, and their interface defects, leading to an elevation of the barrier and the recoverable current collapse effect of p-GaN HEMTs under SC stress.