Analytical model of AlGaN/GaN HEMTs with a partial GaN cap layer

In this paper, a two-dimensional analytical model of AlGaN/GaN HEMTs with a partial GaN cap layer is developed. Under two assumptions of complete depletion and incomplete depletion, the analytical expressions for the channel potential and electric field distributions are obtained on the basis of Poisson's equation. The dependences of the channel potential and electric field distributions on various thicknesses and lengths of the partial GaN cap layer are demonstrated. The analytical model is verified in comparison with the ISE TCAD simulation. A fair consistency between the analytical and numerical results indicates the validity of the proposed analytical model. This method provides a reference to model other different GaN-based power devices.