Fabrication and characterization of V-gate AlGaN/GaN high electron mobility transistors

V-gate GaN high electron mobility transistors (HEMTs) are fabricated and investigated systematically. A V-shaped recess geometry is obtained using an improved Si₃N₄ recess etching technology. Compared with standard HMETs, the fabricated V-gate HEMTs exhibit a 17% higher peak extrinsic transconductance due to a narrowed gate foot. Moreover, both the gate leakage and current dispersion are dramatically suppressed simultaneously, although a slight degradation of frequency response is observed. Based on a two-dimensional electric field simulation using Silvaco "ATLAS" for both standard HEMTs and V-gate HEMTs, the relaxation in peak electric field at gate edge is identified as the predominant factor leading to the superior performance of V-gate HEMTs.