Understanding contact gating in Schottky barrier transistors from 2D channels

TL;DR

This paper introduces a two-path model to accurately describe the sub-threshold behavior of back-gated Schottky barrier FETs with 2D channels, highlighting the role of contact gating in device performance.

Contribution

A novel two-path model combining conventional SB-FET theory with contact gating effects, validated against extensive experimental data from WSe2 devices.

Findings

The model accurately predicts sub-threshold characteristics.

Contact gating significantly influences carrier injection.

The approach aids analysis of ultrathin channel devices.

Abstract

In this article, a novel two-path model is proposed to quantitatively explain sub-threshold characteristics of back-gated Schottky barrier FETs (SB-FETs) from 2D channel materials. The model integrates the 'conventional' model for SB-FETs with the phenomenon of contact gating - an effect that significantly affects the carrier injection from the source electrode in back-gated field effect transistors. The two-path model is validated by a careful comparison with experimental characteristics obtained from a large number of back-gated WSe2 devices with various channel thicknesses. Our findings are believed to be of critical importance for the quantitative analysis of many three-terminal devices with ultrathin body channels.