Physical simulations and experimental results of 4H-SiC MESFETs on high purity semi-insulating substrates

In this paper we report on DC and RF simulations and experimental results of 4H-SiC metal semiconductor field effect transistors (MESFETs) on high purity semi-insulating substrates. DC and small-signal measurements are compared with simulations. We design our device process to fabricate n-channel 4H-SiC MESFETs with 100 μm gate periphery. At 30 V drain voltage, the maximum current density is 440 mA/mm and the maximum transconductance is 33 mS/mm. For the continuous wave (CW) at a frequency of 2 GHz, the maximum output power density is measured to be 6.6 W/mm, with a gain of 12 dB and power-added efficiency of 33.7%. The cut-off frequency (fT) and the maximum frequency (fmax) are 9 GHz and 24.9 GHz respectively. The simulation results of fT and fmax are 11.4 GHz and 38.6 GHz respectively.