Time-dependent monotonic and non-monotonic dynamic <i>R</i> _DS,ON variations and mechanisms in p-GaN Gate HEMTs

Abstract This paper systematically investigates the non-uniform dynamic on-resistance ( R DS,ON ) behaviors with OFF-state voltage ( V DS,OFF ) in p-GaN gate high electron mobility transistors under varying stress time ( t stress ). A modified dynamic R DS,ON evaluation platform is proposed, enabling a multi-group double pulse tests method. Experimental results show a monotonic increase in R DS,ON with V DS,OFF when t stress is within the millisecond range. As t stress increases, the variations begin to display non-monotonic trends of rising initially and then falling. This discovery for the first time distinguishes and clearly reveals the inconsistency in the variation pattern of dynamic R DS,ON over t stress . Based on leakage sweeping and band diagram analysis, the physical mechanisms are clarified. The monotonic increase stems from enhanced carrier trapping under high electric fields, while sufficient t stress leads to leakage paths and charge redistribution in the device structure, causing non-monotonic variations. These findings highlight the necessity for precise control of t stress to evaluate R DS,ON degradation, offering critical guidance for advancing the reliability and efficiency of GaN-based electron devices in power electronics.