SiC MESFET with a Double Gate Recess

Abstract

In order to increase the output power and drain efficiency, MESFETs in SiC have been made with a double gate recess technique. Typical device characteristics of the MESFETs are drain currents of 380mA/mm, breakdown voltages of 80V and ft/fmax of 10/25 GHz respectively. These transistors exhibit power densities of 3W/mm@3GHz in class AB operation and drain efficiencies of 60%. Packaged devices with 3 mm gate periphery of this type, with via-hole grounding, gave power densities of 1.2 W/mm@6GHz at 50 V drain bias.