Enhanced Ion/Ioff ratio and controlled threshold voltage in multi-layer MoS2 transistors thinned by a reactive-ion etching process

Abstract

Semiconducting two-dimensional (2D) transition metal dichalcogenides (TMDs), such as MoS2, provide advantages such as good surface roughness without dangling bonds, diverse electronic and optical properties, and a desirable bandgap. In particular, multi-layer MoS2 shows great potential for advanced field-effect transistor (FET)-based applications. In this study, multi-layer MoS2 FETs were fabricated and subjected to systematic reactive ion etching (RIE) with CF4 plasma. This process dramatically improved the on-current to off-current (Ion/Ioff) ratio in a device in which the MoS2 channel was thinned. The effective thickness of the MoS2 channel with respect to the doping concentration, fluorinated surface, and maximum depletion width (Dmax) are discussed in detail to verify the experimental results.