Simulation of improved 3D tri-gate 4H-SiC MESFETs with recessed drift region

An improved 3D tri-gate 4H-SiC MESFETs structure with recessed drift region was proposed and its DC and RF electrical performances were studied by numerical simulation. The recessed source/drain drift region of the proposed structure is to eliminate gate depletion layer extension to source/drain to decrease gate-source capacitance as well as to reduce the channel thickness between gate and drain to increase breakdown voltage. The simulated results showed that the maximum theoretical output power density, the cut-off frequency (f_T) and the maximum oscillation frequency (fmax) of the proposed structure are 18.5 W/mm, 19.3 GHz and 74.1 GHz compared to 15.5 W/mm, 16.1 GHz and 55.9 GHz of that of the published 3D tri-gate structure, respectively.