An analytical model for small signal parameters in HEMTs including the effect of source drain extrinsic resistances

A simple analytical model has been developed for small-signal parameters in HEMTs at non-thermal equilibrium. The effect of the source/drain extrinsic resistances has also been included in the model. A charge control model ha s been developed to study various charge components contributing to the dra in current and capacitances within the device. These charges include the co ntribution of the 2DEG and AlGaAs free electrons and the neutralized donors . The I-V model has been modified to include the drain voltage dependence o f the saturation voltage. The validity of the model has been confirmed by c omparing the simulated I-V characteristics with published experimental data . Generally, close form expressions for the small signal device parameters affected by the presence of source/drain extrinsic resistances, in the line ar and saturation region, have been obtained. This type of formulation can be used as a basis for the extraction of intrinsic small signal parameters from measured data. (C) 1999 Elsevier Science Ltd. All rights reserved.