Analytical Modeling of Gate-Stack DG-MOSFET in Subthreshold Regime by Green's Function Approach

Abstract

An accurate analytical model of the gate-stack symmetric double-gate (DG) MOSFET using Green's function approach is developed in this brief. An exact analytical solution to 2-D Poisson's equation is derived in the subthreshold regime of operation, considering 2-D mixed boundary conditions and multizone techniques. It is observed that the Green's function approach of solving 2-D Poisson's equation in both oxides (tox1 and tox2) and silicon region can accurately predict channel potential and subthreshold current (Isub) of gate-stack DG-MOSFET. We further extend our model to mitigate the fringe-induced barrier lowering (FIBL) effect in the gate-stack device, by optimizing the interfacial layer thickness. It is observed that selection of interfacial SiO2 layer as ∼0.75 times of equivalent oxide thickness is necessary to completely mitigate the FIBL effect of SiO2-HfO2-based gate-stack DG-MOSFET. © 2018 IEEE.