An Improved Gate Charge Model of HEMTs by Direct Formulating the Branch Charges

We present an improved gate charge model for High electron mobility transistors (HEMTs) that is di- rect formulated from the branch charges. Different charge modeling procedures based on the charge conservation principle have been discussed and the proposed model is more accurate, easier to be implemented into com- mercial simulators. An improved modeling method on channel length modulation parameter to account for the drain-current kink effect of HEMTs has also been intro- duced. The nonlinear model is verified by comparing the measurements and simulations using 0.25-µ mg ate-length GaAs HEMT devices.