Analytical modeling of a dual material double gate tunnel field effect transistor

Abstract

In this work, closed form expressions of surface potential, electric field, drain current and threshold voltage of a Dual Material Double Gate (DMDG) TFET have been proposed. Potential and field distribution have been derived by applying Gauss law in the lightly doped body region and later tunneling current has been modeled using Kane’s band to band tunneling model. In DMDG TFET device, two different metals over the channel region assist to form a barrier in the channel which restricts the reverse tunneling of the carrier, i.e., tunneling from drain to source. The choice of two metals with different workfunctions helps to increase the ON-current and also to form a barrier in the channel, which reduces the OFFcurrent. Effect of gate bias, drain bias and varying parameters like device length, Si film thickness, metal workfunction, gate dielectric have been studied. A numerical model of the device has been developed in ATLAS, Silvaco. The proposed models have been verified against numerical simulations. Since analytical modeling is crucial in understanding the characteristics of a novel device, the proposed model will be helpful for designing a circuit containing DMDG TFET devices.