Online Degradation Sensing and Mechanism Analysis for p-GaN HEMTs Under Repetitive ESD Stresses Based on Current Transient Feature

Reliability issues have persistently hindered the large-scale commercialization of E-mode GaN high electron mobility transistors with p-GaN gate. Therefore, it is important to sense the degradation of devices timely and understand the failure mechanisms. This paper demonstrates the feasibility of an online degradation sensing method of Schottky-gate p-GaN HEMTs by tracking changes in current transient feature before and after electrostatic discharge stress. Device degradation was induced by subjecting the gate terminal to repetitive electrostatic discharge stress using on-wafer transmission-line pulse testing on gate. Additionally, a boost circuit was used to simulate real-world operating conditions. The degradation phenomenon is quantified by the drain-to-source current switching rate during turn-on transient, measured via a non-intrusive current probe. The experimental results show that the variation of current switching rate correlates with device degradation and can be effectively used to monitor early failure. Furthermore, degradation mechanisms such as trapping effects and current crowding are investigated and verified by technology computer-aided design simulations.