Microwave characterisation and modelling of silicon carbide power MESFETS: towards a nonlinear model

SiC power MESFETs are studied for applications to power amplification in the microwave domain. A small-signal model is explained. It provides the intrinsic bias-dependent parameters of the devices, such as G_m, C_gs, C_ds, C_gd, and the current gain cut-off frequency f_T. It is shown that f_T and G_m decrease with the drain to source bias V_DS, because of self-heating effects. The model also includes temperature dependence and is in good agreement with experiments. This is a first step to non-linear modelling of SiC MESFETs.