Characteristics of AlGaN/GaN HEMTs With Various Field-Plate and Gate-to-Drain Extensions

AlGaN/GaN high-electron-mobility transistors (HEMTs) with various field-plate (FP) and gate-to-drain distance extensions are fabricated and investigated. Experiments are carried out on 20 transistors. Their ON-state resistance (RON), OFF-state breakdown voltage (VBR), RF performance, and low-frequency noise are measured and studied. The FP extension is found to significantly improve the OFF-state breakdown voltage. However, the FP extension obviously weakens the frequency response and power added efficiency performance, because it increases the feedback C_gd. The FP extension is beneficial to the reduction of the electric field intensity at the gate edge of the device and reduces the probability of the injection of electrons into traps, resulting in the reduction of low- frequency noise.