Reproducible Performance Improvements to Monolayer MoS2 Transistors through Exposed Material Forming Gas Annealing

TL;DR

This paper presents an optimized annealing process using forming gas to improve the performance and yield of large-area monolayer MoS2 transistors by reducing organic contamination and interface defects.

Contribution

It introduces an exposed material forming gas anneal (EM-FGA) technique that enhances uniformity and performance of large-area MoS2 FETs, addressing key fabrication challenges.

Findings

Achieved 85% yield in large-area MoS2 FETs.

Reduced organic contamination and molybdenum oxide at interfaces.

Improved uniformity of transistor performance metrics.

Abstract

Metal-mediated exfoliation has been demonstrated as a promising approach for obtaining large-area flakes of 2D materials to fabricate prototypical nanoelectronics. However, several processing challenges related to organic contamination at the interfaces of the 2D material and the gate oxide must be overcome to realize robust devices with high yield. Here, we demonstrate an optimized process to realize high-performance field-effect transistor (FET) arrays from large-area (~5000 um2) monolayer MoS2 with a yield of 85 %. A central element of this process is an exposed material forming gas anneal (EM-FGA) that results in uniform FET performance metrics (i.e., field-effect mobilities, threshold voltages, and contact performance). Complementary analytical measurements show that the EM-FGA process reduces deleterious channel doping effects by decreasing organic contamination, while also reducing the prevalence of insulating molybdenum oxide, effectively improving the MoS2-gate oxide interface. The uniform FET performance metrics and high device yield achieved by applying the EM-FGA technique on large-area 2D material flakes will help advance the fabrication of complex 2D nanoelectronics devices and demonstrates the need for improved engineering of the 2D material-gate oxide interface.