Determination of the Gate Breakdown Mechanisms in p-GaN Gate HEMTs by Multiple-Gate-Sweep Measurements

In this work, we studied the gate breakdown (BD) mechanisms of p-GaN gate AlGaN/GaN HEMTs by a novel multiple-gate-sweep-based method. For the first time, three different BD mechanisms were observed and identified separately in the same devices: the metal/ p-GaN junction BD, the p-GaN/AlGaN/GaN junction BD, and the passivation-related BD. This method is an effective method to determine the BD mechanisms. The different BD mechanisms were further confirmed by scanning electron microscopy (SEM). Finally, the temperature dependences of the three BD mechanisms were measured and compared. This analysis method was also employed in the devices with a different passivation material and showed its applicability.