Dynamic ON-State Breakdown of GaN-on-Si HEMT

Abstract

We apply ramp-drain-voltage-(. Vd) -stress (RVS) method to characterize breakdown loci of GaN-on-Si HEMTs under high-power on state conditions. We observe that GaN-onSi HEMTs have distinct breakdown dependencies in the fully-ON state (when conductive current ≥400mA/mm) and semi-ON state (when conductive current <400mA/mm). In the fully-ON state, the breakdown loci are independent of HEMT top barrier options (InAIN, AIGaN, or AIN) while in the semi-ON state, the breakdown loci have clear top barrier dependences. We systematically screen key parameters behind the fully-ON breakdown voltages loci. We report significant dependences of fully-ON breakdown on device width, gate-to-drain spacing Lgd and RVS sweep rate. The dependence of fully-ON breakdown on device width results from self-heating effects. The dependence of fully-ON breakdown on Lgd and RVS sweep rate suggests correlation between device failure and dynamic trapping effects in the gate-to-drain access region.