A compact and accurate analytical charge control model for finding gate capacitance of AlmGa1-mN/GaN MODFET is presented. This temperature dependent model incorporates the effect of strain relaxation, donor neutralization and free carrier generation in the AlmGa1-mN layer. Non-linear Fermi potential (E-F)-variation with the sheet carrier concentration (n(s)), and the charge induced in the two-dimensional electron gas (2-DEG) due to highly dominant effects of spontaneous and piezoelectric polarization at the heterojunction of MODFET are also considered. The model is based on closed form expression and does not involve any fitting parameter or elaborate computation. Agreement of calculated data with published simulated/experimental data proves the validity and applicability of the model. (c) 2005 Elsevier Ltd. All rights reserved.