DC and RF characteristics of SiC MESFETs with different channel doping concentrations under the gate

Abstract

A Silicon carbide (SiC) metal semiconductor field effect transistor (MESFET) with step doping under the gate is proposed. The channel under the gate is divided into two Source Side (SS) and Drain Side (DS) regions with the same lengths and thicknesses, but with different doping levels. Changes that occur in the breakdown voltage, DC trans-conductance, drain current, gate-source capacitance, cut off frequency, and short channel effect as a function of different source side (NSS) and drain side (NDS) channel doping levels are studied in details. Simulation results illustrate that a larger NSS compared to NDS improves the breakdown voltage. On the other hand, decreasing NSS, reduces the gate-source capacitance. A larger channel doping concentration under the gate improves the short channel effect such as DIBL. With varying NSS and NDS, the DC transconductance has a nonlinear variations. Also, simulation results demonstrate that NSS effects on the DC and RF characterization of SiC-MESFET is more than that of NDS.