Numerical simulation of small-signal microwave performance of 4H–SiC MESFET

Small-signal high frequency characteristics of 4H–SiC MESFET has been studied by using two-dimensional numerical drift-diffusion model in frequency domain. Non-ideal Schottky boundary conditions have been introduced that take into account a thin interfacial layer and interface energy states. It has been demonstrated that the 10 dB/dec small-signal current gain roll-off can be attributed to the existence of high density interface states at the metal–semiconductor interface. It has been found that as the gate length is reduced to 0.1 μm, fT and fmax may reach as high as 30 and 62 GHz, respectively.