An Improved 4H-SiC MESFET with a Partially Low Doped Channel

An improved 4H-SiC metal semiconductor field effect transistor (MESFET) based on the double-recessed MESFET (DR-MESFET) for high power added efficiency (PAE) is designed and simulated in this paper and its mechanism is explored by co-simulation of ADS and ISE-TCAD software. This structure has a partially low doped channel (PLDC) under the gate, which increases the PAE of the device by decreasing the absolute value of the threshold voltage ( ), gate-source capacitance ( ) and saturation current ( ). The simulated results show that with the increase of , the PAE of the device increases and then decreases when the value of is low enough. The doping concentration and thickness of the PLDC are respectively optimized to be = 1 × 10 cm and = 0.15 μm to obtain the best PAE. The maximum PAE obtained from the PLDC-MESFET is 43.67%, while the PAE of the DR-MESFET is 23.43%; the optimized PAE is increased by 86.38%.