Numerical Simulation of 4H-SiC Metal Semiconductor Field Transistors

This work simulates the performance of 4H-SiC MESFETs and establishes the optimum device structure for dc and rf applications that operate at high voltages. Devices with various channel doping, buffer layer doping, recess thickness, gate-to-drain spacing and temperatures of operation are considered. The simulation results reveal that a p-type buffer layer of 5×10¹⁵ cm⁻³ and a channel layer of 1×10¹⁷ cm⁻³ yield favorable results. The cut-off frequency is 22.53 GHz, the maximum transconductance is 50.55 mS/mm, the drain saturation current is 239.76 mA/mm and the breakdown voltage is 70.40 V. The breakdown voltages increase to 90.2 V as the gate-to-drain spacing increases to 1 µm. Based on these simulation results, new 4H-SiC MESFET designs can be calibrated.