Ultra-Thin SiGe in the Source Modifies Performance of Thin-Film Tunneling FET

TL;DR

This paper investigates how integrating ultra-thin SiGe in the source of a thin-film tunneling FET improves its electrical performance by reducing sub-threshold swing and OFF-current, and increasing the ON-OFF ratio through simulation.

Contribution

It introduces novel source structures with ultra-thin SiGe in TFETs and analyzes their impact on device performance using simulations and band diagram studies.

Findings

Reduced sub-threshold swing and OFF-current

Increased ON-OFF ratio compared to conventional TFETs

Optimal SiGe thickness and Ge mole fraction identified

Abstract

In this work, the source structure of an n-type thin-film tunneling FET is engineered to get better performance. An ultra-thin SiGe along with Si is used in the source of silicon-based TFET. Two structures are compared with conventional TFET, one, SiGe is located on the top of Si in the source and another one in reverse. Simulations approve these structures can reduce sub-threshold swing, OFF-current several times, and increase the ON-OFF ratio. Band diagram for conduction and valance bands are investigated and band to band tunneling (BTBT) generation rate is used to find better performance. We find current flows at Si in the source with the wider bandgap. Ge mole fraction of SiGe is varied and its effects on the performance of TFET are studied. The SiGe thickness for both structures is explored to obtain the best thickness for SiGe.