A Generalized Approach to Determine the Switching Reliability of GaN HEMTs on-Wafer Level

In this work, a detailed analysis of the turn-on behavior of E-mode p-GaN HEMT is reported, with a focus on the impact of hard switching conditions. The study is carried out by means of a novel custom system, developed with the purpose of investigating - on wafer level- the impact of hard switching stress in terms of dynamic on-resistance (R DSON ), turn-on switching locus, and power dissipation. The novelty of our approach comes from the high speed of the turn-on commutations (in the range of 10 V/ns), which enables a realistic assessment of the power device performances before the packaging-level, thus shortening the technological development loop. The DUT is tested at high frequency (100 kHz) and different stress conditions: (i) by increasing the voltage at the drain side (V DD ), and (ii) by increasing the load capacitance to study the effect of the slew-rate on the dynamic R DSON of GaN devices. The results indicate that even the very short hard switching times reached during fast commutation (few ns) can lead to the increase in dynamic R DSON of power GaN devices, thus providing important information on the trapping kinetics of hot electrons.