Investigation of Breakdown Characteristics in High-voltage GaN-HEMTs

Abstract

The breakdown mechanism of high-voltage GaN-HEMTs was investigated using the experimental I-V characteristics and two dimensional device simulation results. Especially in the vicinity of breakdown voltage, we clarify that breakdown characteristics are determined by the positive feedback of five steps, which are (1) impact ionization by substrate leakage current, (2) hole accumulation under the gate (3) gate potential barrier lowering, (4) increase of source leakage current and (5) enhancement of the impact ionization at the drain electrode edge.