A Surface-Potential Based Compact Model for GaN HEMTs Directly Incorporating Polarization Charges

A method to incorporate polarization charges at heterojunctions in compact models for transistors is presented. By including the polarization sheet charge as a Dirac delta function, the Poisson equation is solved to yield a closed equation for the surface potential. A compact model for transistors based on the surface potential incorporating polarization charges describes the on-state as well as the off-state regimes of device operation. The new method of incorporating polarization charges in compact models helps make a direct connection to the material properties of the transistor. The current-voltage (I-V) curves generated by this model are in good agreement with the experimental data for GaN HEMTs.