In this study, the impact of the source field plate on the breakdown voltage, low-frequency noise, and high-frequency characteristics of GaN-based enhancement mode metal-oxide-semiconductor high-electron mobility transistors (MOSHEMTs) with fin-gated multiple nanochannels and double-two-dimensional electron gas channels was explored. Compared with the breakdown voltage of 752 V and the normalized noise power density of 1.3 × 10−13 Hz−1 of the device without the source field plate, they were 784 V/3.3 × 10−14 Hz−1, 859 V/1.5 × 10−14 Hz−1, and 825 V/2.5 × 10−14 Hz−1 for the device with source field plate lengths of 7 μm, 8 μm, and 9 μm, respectively. The breakdown voltage and the normalized low-frequency noise power density were improved. The extent to which these characteristics were improved was affected by the length of the source field plate. When the edge of the source field plate was located at the central position between the source and drain, the highest breakdown voltage and the lowest normalized noise power density were achieved. However, the high-frequency characteristics were degraded by incorporating a longer source field plate owing to the larger induced parasitic capacitance.
Chen et al. (Sat,) studied this question.