E-Mode p-GaN Gate Punch-Through HEMT with Robust Non-Destructive Drain Breakdown

This work presents an E-mode p-GaN gate punch-through HEMT (PT-HEMT) which could achieve repetitive non-destructive breakdown, addressing the long-standing issue in conventional GaN HEMTs—the lack of avalanche robustness. The PT-HEMT features an array of p-GaN islands along the width of the device as control gate, and a thinned p-GaN layer extending from gate toward drain as punch-through gate (PT-gate). In the OFF-state, high drain bias induces full depletion of the PT-gate, so the underlying 2DEG channel is punched through, resulting in a non-destructive breakdown. Thus, drain voltage is clamped at punch-through voltage lower than that for destructive breakdown to dissipate transient overvoltage spikes. This mechanism is validated by the matched values between PT-gate depletion voltage and punch-through breakdown voltage. For 650-V rating, PT-HEMT with LGD = 12 μm achieves a non-destructive breakdown voltage of 874 V. The punch-through breakdown exhibits a positive temperature coefficient. Under current-driven breakdown tests, the PT-HEMT survives more than 100 repetitive breakdown cycles, with negligible degradation of threshold voltage, RON, and dynamic RON. The PT-HEMTs are empowered with an inherent capability to handle transient overvoltage spikes in high-power switching applications.