2-D Analytical Model for Electrical Characteristics of Dual Metal Heterogeneous Gate Dielectric Double-Gate TFETs with Localized Interface Charges

Abstract

In this paper, a 2-D analytical model for electrical characteristics such as surface potential, drain current, and threshold voltage of dual metal (DM) heterogeneous gate dielectric (HGD) double-gate (DG) tunnel field-effect transistors (TFETs) with localized interface charges have been investigated. The surface potential model has been used to derive a compact model for the electric field by including the effects of the localized charges near the source/channel junction, mobile charges in channel region and the charges in the depletion regions formed at source/channel and drain/channel junctions. The band-to-band tunneling (BTBT) generation rate has been developed by considering the effect of the electric fields at both the source/channel and drain/channel junctions. The drain current has then been derived for all gate bias (i.e. ambipolar to forward gate bias) by using the tangent line approximation method. Finally, the threshold voltage model has been developed by using the concept of shortest tunneling path of DM-HGD DG-TFET under study. The impact of localized interface charges on the drain current and threshold voltage by varying the device dimensions are also investigated. The validity of our model results are verified by numerical simulation results obtained from 2-D device simulator ATLAS™ .