MoS2 Nanoribbon Transistors: Transition from Depletion-mode to Enhancement-mode by Channel Width Trimming

TL;DR

This study investigates how reducing the channel width of MoS2 MOSFETs affects their electrical properties, revealing a transition from depletion to enhancement mode and the impact of thickness on threshold voltage shifts.

Contribution

It demonstrates the transition from depletion-mode to enhancement-mode in MoS2 transistors through channel width trimming and analyzes the effects of thickness and width on threshold voltage.

Findings

Channel conductance scales linearly with width

Threshold voltage shifts positively as width decreases below 200 nm

Thinner MoS2 layers exhibit larger threshold voltage shifts

Abstract

We study the channel width scaling of back-gated MoS2 metal-oxide-semiconductor field-effect transistors (MOSFETs) from 2 {\mu}m down to 60 nm. We reveal that the channel conductance scales linearly with channel width, indicating no evident edge damage for MoS2 nanoribbons with widths down to 60 nm as defined by plasma dry etching. However, these transistors show a strong positive threshold voltage (VT) shift with narrow channel widths of less than 200 nm. Our results also show that transistors with thinner channel thicknesses have larger VT shifts associated with width scaling. Devices fabricated on a 6 nm thick MoS2 crystal underwent the transition from depletion-mode to enhancement-mode.