Performance enhancement of triple material double gate TFET with heterojunction and heterodielectric

Abstract

In this paper, we proposed a 2 dimensional model of tripple material double gate Tunnel Field Effect Transistor (TM-DG TFET) with hetero-junction formed by germanium and silicon materials in the source-channel junction and heterodielectric gate stack is used with Silicon Dioxide (SiO₂) and Hafnium Dioxide (HfO₂) as dielectric materials. The electrical characteristics like surface potential, electric field, drain current and transconductance are demonstrated for the device by using commercially available 2D numerical device simulator Silvaco TCAD ATLAS. The variation of the drain currnet or ON current with the varying channel length (L), doping concentration of drain and source (N_A and N_D), thickness of device (t_si) and effective oxide layer thickness (t_ox) of the device is evaluated and presented. It is demonstrated that the proposed TM-DG TFET structure has better performance than single material and double material TFET. The proposed model shows a lower ambipolar current and a better I_ON/I_OFF ratio. Moreover, the influence of Germanium/Silicon hetero-junction has reduces the tunneling barrier width is exactly depicted. Hence the ON current (10⁻³A) of the proposed device is improved at the level of CMOS transistors.