Self-consistent Monte Carlo simulation are reported for GaN/SiC HFETs. Hot carrier scattering rates are determined by fitting experimental ionisation coefficients and the doping character of GaN is obtained from substrate bias measurements. Preliminary simulations for a simple model of the GaN surface are described and results are found to be consistent with experimental data. Planer GaN/SiC HFETs structures with a 60 nm GaN pseudomorphically strained layer were simulated, where the spontaneous and piezoelectric polarization effects were taken into account. The polarization effects was shown to not only increase the current density, but also improve the electron transport in the interface layer by inducing a higher electron density to the positive polarized sheet and away from the buffer layer.

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