2-D Analytical Modeling of Threshold Voltage for Graded-Channel Dual-Material Double-Gate MOSFETs

A 2-D analytical model for the surface potential and threshold voltage of graded-channel dual-material double-gate (GCDMDG) MOSFETs obtained by intermixing the concepts of graded doping in channel and dual material in gate engineering has been proposed. The parabolic approximation method has been explored for determining the potential distribution function of the device by solving Poisson's equation with suitable boundary conditions. The threshold voltage roll-off, drain-induced barrier lowering and lateral electric field have also been examined. The effects of different device parameters on device performance have been evaluated to check its figure-of-merit over the graded-channel double-gate (GCDG) and dual-material double-gate (DMDG) structures. For validation of the proposed model, the results have been compared with the numerical simulation data obtained by ATLAS™, a 2-D device simulator from SILVACO.