Statistical Analysis of Contacts to Synthetic Monolayer MoS2

TL;DR

This paper presents a statistical analysis of gold contacts to monolayer MoS2, achieving record low contact resistance and examining the effects of dielectric encapsulation on device variability, with insights into modeling deviations.

Contribution

It provides the first statistical study of Au contacts to monolayer MoS2 using TLM structures, reporting the lowest contact resistance and analyzing encapsulation effects.

Findings

Record low contact resistance of 330 ohm-um achieved.

Dielectric encapsulation affects contact resistance variability.

Deviations observed in TLM model for short-channel devices.

Abstract

Two-dimensional (2D) semiconductors are promising candidates for scaled transistors because they are immune to mobility degradation at the monolayer limit. However, sub-10 nm scaling of 2D semiconductors, such as MoS2, is limited by the contact resistance. In this work, we show for the first time a statistical study of Au contacts to chemical vapor deposited monolayer MoS2 using transmission line model (TLM) structures, before and after dielectric encapsulation. We report contact resistance values as low as 330 ohm-um, which is the lowest value reported to date. We further study the effect of Al2O3 encapsulation on variability in contact resistance and other device metrics. Finally, we note some deviations in the TLM model for short-channel devices in the back-gated configuration and discuss possible modifications to improve the model accuracy.