4H-SiC MESFET with a novel MOS gate controlled spacer layer structure

A novel structure of 4H-SiC MESFETs is proposed which focuses on surface trap suppression. A MOS gate controlled spacer layer is shown to improve both DC and AC characteristics due to suppressed surface effect and decreased gate capacitance. A very high power density of 6.1 W/mm is obtained at S band operation. Compare with the well recognized buried gate structure, there is a significant improvement in the power density of about 18%. Also, a 12% and a 15% improvement in f_T and f_max are obtained in AC simulation, respectively.