Improved 4H–SiC MESFET with bulgy channel

Abstract

This paper proposes an improved 4H–SiC metal semiconductor field effect transistor with a bulgy channel (BC-MESFET) whose gate-source and gate-drain drift regions are shifted downward 0.1 μm relative to the channel below the gate. By introducing recesses at both ends of the metal gate, both the DC and AC characteristics of the structure have been greatly improved. The simulation results show that the saturation current of BC-MESFET is 30% higher than that of DR-MESFET, and the breakdown voltage is 78% higher. Therefore, the maximum output power density has a significant increase of 137%. In terms of RF, since the gate-source capacitance of the BC-MESFET structure is 31% lower than that of the DR-MESFET, its characteristic frequency is also improved by 18%. In this paper, aiming at high power added efficiency (PAE), the bump height H of the buffer layer under the lower gate is optimized, and a structure with 25% higher PAE than DR-MESFET is obtained.