A novel 4H-SiC MESFET with symmetrical lightly doped drain for high voltage and high power applications

Abstract

A novel 4H-silicon carbide metal semiconductor field effect transistor with symmetrical lightly doped drain (SLDD-MESFET) for high voltage and high power applications is proposed in this paper. The 2-D simulations show that the lightly doped region on the drain side of the gate edge can greatly increase the breakdown voltage of the device. And the lightly doped region on the source side of the gate edge can increase the RF characteristics. Compared with the double-recessed structure (DR-MESFET), the lightly doped drain has a higher breakdown voltage and forms a new electric field peak, which increases the breakdown voltage of the device from 109 V to 151 V, an increase of 38.5%. And the maximum output power density is increased from 5.42 W/mm to 7.54 W/mm, an increase of 39.1%. Moreover, by introducing the lightly doped source, the gate-source capacitance of the device is reduced by 15%, which increases the device's cut-off frequency and maximum oscillation frequency by 13.3% and 6.4%, respectively. The improvements in both DC and RF characteristics make the proposed structure a superior device for high voltage and high power applications.