Characterizations of Enhancement-Mode Double Heterostructure GaN HEMTs With Gate Field Plates

With the purpose to increase the threshold voltage of the enhancement mode GaN high-electron mobility transistors, we fabricated devices with gate field plates on the p-GaN/AlGaN/GaN/AlGaN double heterostructures. We observed an existence of a subthreshold region from the current-voltage transfer curves. The threshold voltage of the device extracted based on linear extrapolation method is much higher than that of a typical device without a gate field plate. We investigated electrical properties based on carrier distributions with the influence of gate electric field at different channel regions.