Surge Current Capability and Failure Modes of 650 V p-GaN Gate HEMTs: A Multiphysics Study on Thermal–Electrical Coupling Effects

In this study, we present a comprehensive comparative analysis of the surge current capability in the third quadrant for four commercial 650 V p-GaN gate HEMTs. Temperature-dependent experiments reveal varying degrees of negative correlation between surge current capability and device junction temperature across the four devices. Gate leakage testing and the decapsulation of failed devices identified two distinct failure modes. Through failure analysis techniques and TCAD simulations, the characteristics of these failure modes were thoroughly revealed. For Failure Mode I, the combined impact of electrical and thermal stress during the surge current process leads to extensive damage in the upper interconnect metal layer. For Failure Mode II, degradation of the metal to p-GaN Schottky contact under a strong electric field causes a rapid increase in the gate current, and the high gate current, coupled with the strong electric field, results in severe electromigration of the gate metal. Among the four tested devices, those exhibiting higher surge energy are more prone to gate damage, making them more susceptible to Failure Mode II.