Study of Time-Dependent Degradation of Reverse Biased AlGaN/GaN HEMTs

This paper analyzes the kinetics of the gate-edge degradation on GaN HEMTs by means of constant voltage tests at different reverse biases. Starting from many literature reports and recent evidences within this topic, this work provides an interpretation for both recoverable and permanent modifications of the main device characteristics induced by reverse bias stress. In particular, the paper highlights that the exposure to reverse-bias can induce recoverable changes in the gate current and permanent degradations by means of the generation of vertical parasitic leakage paths, showing the time-dependence of the failure mechanism and the role of the gate voltage as accelerating factor.