Study of the electrical parameters of a dual-material double-gate TFET using a strained type Ⅱ staggered Ge_(1-x-y)Si_xSn_y/Ge_(1-a-b)Si_aSn_b heterojunction

摘要

A strained Ge_(1-x-y)Si_xSn_y/Ge_(1-a-b)Si_aSn_b direct type Ⅱ staggered heterojunction n-channel tunneling field-effect transistor (FET) with a dual-material double gate is proposed herein. A high-K gate dielectric is used to improve the overall device performance. The energy bandgap for strained Ge_(1-x-y)Si_xSn_y grown on a relaxed Ge_(1-a-b)Si_aSn_b layer is determined using the generalized approach of Menendez and Kouvetakis (MK). Poisson's equation is solved by using a parabolic approximation to determine the surface potential and electric field. The drain current is calculated using the tunneling generation rate obtained from Kane's model. A significant improvement of the drain current is observed as compared with that of previously reported Si-based TFETs.