Reliability of metallic contact properties of 2D semiconductors

Electrical performances of semiconductor devices fabricated with 2-dimensional (2D) channel materials such as transition metal dichalcogenides (TMDCs) are strongly affected by the metallic contact interfacing with a 2D material. There have been various researches to investigate the interface formed between metals and 2D materials, by revealing typical figures of merit of contact properties which are contact resistance, Fermi level pinning, and Schottky barrier height (SBH). We find that the data of these contact properties obtained from 2D devices show large standard deviation, requiring to assess reliability of the contact properties of 2D semiconductors. In this study, we conducted experimental studies on how to get the reliable Schottky barrier heights (SBHs) formed at the interface of a metal (Ti) and a 2D material (MoS₂). Here, we performed annealing for the purpose of decreasing contact resistance and investigating temperature dependent electrical behaviors of devices of various 2D thicknesses and channel lengths, together with the SBH analysis. By conducting this research, we can provide a practical guideline to obtain highly reliable contact properties of 2D semiconductor devices.