Dual-material double-gate tunnel FET: gate threshold voltage modeling and extraction

Abstract

A new analytical model for the gate threshold voltage ($$V_\mathrm{TG}$$VTG) of a dual-material double-gate (DMDG) tunnel field-effect transistor (TFET) is reported. The model is derived by solving the quasi-two-dimensional Poisson's equation in the lightly doped Si film and employing the physical definition of $$V_\mathrm{TG}$$VTG. A numerical simulation study of the transfer characteristics and $$V_\mathrm{TG}$$VTG of a DMDG TFET has been carried out to verify the proposed analytical model. In the numerical calculations, extraction of $$V_\mathrm{TG}$$VTG is performed based on the transconductance change method as already used for conventional metal---oxide---semiconductor FETs (MOSFETs). The effects of gate length scaling, Si film thickness scaling, and modification of the gate dielectric on $$V_\mathrm{TG}$$VTG are reported. The dependence of $$V_\mathrm{TG}$$VTG on the applied drain bias is investigated using the proposed model. The proposed model can predict the effect of variation of all these parameters with reasonable accuracy.