Local Back-Gate Monolayer MoS2 Transistors with Channel Lengths Down to 50 nm and EOT ∼ 1 nm Showing Improved $I_{\text{on}}$ using Post-Metal Anneal

Two-dimensional (2D) semiconductors such as monolayer (1L) MoS 2 are promising candidates for ultra-scaled field-effect transistors (FETs) owing to their good mobilities at sub-nanometer channel thicknesses, which ideally allows for excellent gate control. Although many advancements have been recently made in the fields of material growth, dielectric formation, and contact engineering [1]–[3], comprehensive and reproducible analyses of well-scaled 2D-FETs are still needed. In this work, we demonstrate a statistical analysis of local back-gated (LBG) monolayer MoS 2 FETs fabricated with Au contacts on ∼6 nm (physical thickness) HfO 2 gate dielectric, down to channel lengths of $L_{\text{ch}} = 50$ nm, enabling on-state currents up to $I_{\text{on}} = 534\ \mu \mathrm{A}/\mu \mathrm{m}$ at $V_{\text{DS}} =1$ V. Further, we utilize NH3 post-metal annealing (PMA) and demonstrate a reproducible improvement of $I_{\text{on}}$ as well as a reduction in contact resistance ( $R_{\mathrm{C}}$ ), obtaining $R_{\mathrm{C}}=420\pm 210\ \Omega\cdot\mu \mathrm{m}$ .