High breakdown voltage 4H-SiC MESFETs with floating metal strips

Abstract

A high breakdown voltage 4H-SiC MESFET with floating metal strips (FMS) was proposed. The maximum electrical field of the MESFET gate is clamped after surface depletion layer punch through to FMS. The optimized results showed that the breakdown voltage of the 4H-SiC MESFET with two strips and one strip are 180% and 95% larger than that of the conventional one without FMS and meanwhile maintain almost same saturation drain current. The maximum theoretical output power density of the 4H-SiC MESFET with two strips and one strip are 14.5 W and 10.0 W compared to 4.8 W of the conventional structure. The cut-off frequency ( f T) of 14.7 GHz and 15.6 GHz and the maximum oscillation frequency ( f max) of 44.8 GHz and 48.7 GHz for the 4H-SiC MESFET with two strips and one strip are obtained respectively, which is just a little bit lower than that of the conventional structure.