A modified model for Si/SiGe MOS-gate delta-doped HEMTs

An analytical model for threshold voltage (Vth) and minimum gate voltage (Vtl) of Si/SiGe MOS-gate delta-doped HEMT is presented in this letter. The model is valid for any width of the delta-doped layer and any distance of the layer from the Si/SiO2 interface. Using the model, Vth and Vtl of a Si/SiGe MOS-gate delta-doped HEMT of known dimensions are calculated. To investigate the effect of variation of the width of the delta-doped layer, the threshold voltage and the minimum gate voltage have been plotted against the width. Medici™ simulation have been performed on the same device to evaluate Vth and Vtl for different delta-doped layer widths. The simulation results are in good agreement with the results found using the analytical model.