Short channel threshold dependence of the inversion channel heterostructure field effect transistor

The threshold voltage dependence on the channel length for the inversion channel HFET is investigated. Modifying the charge equations to account for source and drain depletion into the channel region yields a length dependent threshold voltage equation. It is shown theoretically that the threshold may increase or decrease with decreasing gate length as the doping parameters are changed, which is supported by experiment. Using the new threshold equation parameters have been found which should allow length invariant thresholds