Controlling ambipolar behavior and improving radio frequency performance of hetero junction double gate TFET by dual work-function, hetero gate dielectric, gate underlap: Assessment and optimization

Abstract

In this paper, investigation for different configurations of N-type Hetero Junction Double Gate Tunnel Field-Effect Transistor (HJ-TFET) with Dual metal gate work function and hetero gate dielectric material along with gate underlap is performed to achieve improvements in DC and analog/RF performances. In this regard, the creation of hetero-junction using band gap engineering maintains the lower energy band and higher energy band at source/channel and drain/channel interface respectively to provide high ON current and low ambipolar behavior. A high-density layer of N+ type concentration is added at source/channel junction to obtain abruptness at the same. Further, application of work function engineering on the gate electrode over the channel specified as Tunnel gate (M1) towards the source region and Auxiliary gate (M2) towards the drain region facilitates to achieve higher ON-state current at the cost of poor analog/RF responses. In this concern, hetero gate dielectric and gate under-lap concepts are implied to reduce parasitic capacitances which enhance RF performance of the device. Furthermore, optimization of work function for tunnel gate and the auxiliary gate has been performed to assess the optimum values of work function.