Numerical simulation of 4H-SiC MESFETs with varied p-buffer layer thickness for microwave power device applications

An improved 4H-SiC MESFETs with varied p-buffer layer thickness is proposed, and the static and dynamic electrical performances are analyzed in this paper. The variation in p-buffer layer depth leads to the change in the active channel thickness and modulates the electric field distribution inside the channel. Detailed numerical simulations demonstrate that the saturation drain current and the maximum theoretical output power density of the proposed structure are about 30% and 37% larger than those of the conventional structure. As compared to the conventional MESFETs, the cut-off frequency and the maximum oscillation frequency of the proposed MESFETs increase from 12.5 and 51GHz to 14.5 and 62 GHz, respectively.