Gate Damage Mechanism of Schottky-Type p-GaN Gate HEMTs in Reverse Conduction Mode Under Surge Current Stress

In this paper, the gate damage mechanism of Schottky-type p-GaN gate high electron mobility transistors (HEMTs) in reverse conduction mode under surge current stress is investigated. Single and repetitive stress experiments and mix-mode simulations are carried out. For the device subjected to the surge current exceeding the rated current, the gate-to-channel voltage is very high due to the self-heating effect. It will cause significant thermally-assisted tunneling of holes at the gate Schottky junction. Under a single stress with an extremely high current, the Schottky junction breakdown will occur, leading to the subsequent device burnout. Under the repetitive stress below the single failure current, new donor traps can be generated in the p-GaN layer, causing irreversible gate degradation. It is confirmed by C
G
-V
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characteristics and recovery experiments.