Threshold Voltage Behavior and Short-Circuit Capability of p-Gate GaN HEMTs Depending on Drain- and Gate-Voltage Stress

In this study, the impact and correlation of drain- and gate-voltage stress on the threshold voltage of commercially available p-gate GaN HEMTs are investigated. This is based on single-pulse measurements acquired with a custom pulse setup, thus the transient behavior can be determined and subsequently translated into dc characteristics. As a novelty, measurements of the threshold voltage for short-circuit stress of up to 600 V are shown. As a result, a constant threshold voltage shift is observed for on-state drain-voltage stress, while off-state drain-voltage and gate-voltage stress lead to a threshold voltage instability. Finally, drain stress and gate stress appears to superimpose, consequently already application-relevant gate-driving conditions show a drastic impact of the short-circuit capability.