Reliability Assessment of Double-Gated Wafer-Scale MoS2 Field Effect Transistors through Hysteresis and Bias Temperature Instability Analyses

Abstract

2D field-effect transistors (FETs) based on transition metal dichalcogenides (TMDs) are a potential replacement for silicon transistors at sub-12 nm channel lengths (LG). Here, we demonstrate initial reliability and performance for double-gated NMOS FETs based on molybdenum disulfide (MoS2) as a channel material with a HfO2 back gate and a Al2O3/HfO2 top gate stack fabricated in an industry lab. We present a comprehensive analysis of hysteresis curves obtained at varying sweep rates of the top gate bias (VTG) for varying temperatures (T), and static back gate biasing conditions (VBG) as well as bias temperature instability (BTI) measurements. Our primary objective is to assess the impact of charge trapping from the channel and the gate side as well as ion diffusion on the observed degradation behavior. Our analysis reveals excellent stability in terms of hysteresis as well as good behaviour in terms of BTI relative to published 2D FETs, even though it is still higher than in commercial Si/SiO2/HfO2 stacks.