An Above Threshold Model for Short-Channel DG MOSFETs

An above-threshold I-V model is developed for short-channel double-gate (DG) MOSFETs. It is a non-gradual channel approximation (non-GCA) model that takes into account the contribution to carrier density from the encroachment of source-drain bands into the channel. At low-drain bias voltages, the effect appears as a gate-voltage-dependent reduction of channel resistance, with stronger effects at low gate overdrives. At high-drain biases, the intersection of source band encroachment with the gate-controlled channel potential leads to a point of virtual cathode a small distance from the source. By incorporating the depletion of carriers in the source and drain regions into the boundary conditions, the I-ds-V-ds and I-ds-V-gs characteristics generated by the model are shown to be consistent with TCAD simulations.