Electrical Characteristics of ML and BL MoS₂ GAA NS FETs With Source/Drain Metal Contacts

Abstract

This paper reports source/drain (S/D) contact issues in monolayer and bilayer (BL) $\mathrm {MoS_{2}}$ devices through density-functional-theory (DFT) calculation and device simulation. We begin by analyzing material properties and van der Waals gaps at metal contacts of $\mathrm {MoS_{2}}$ using DFT calculation. These results are then used for device simulation, aligning closely with experimental data. For the first time, the model is extended to 3D gate-all-around (GAA) nanosheet (NS) field-effect transistors (FETs) simulation, enabling contact resistance $(R_{C})$ estimation. This work addresses key challenges by reducing computational demands compared to non-equilibrium Green function method and accurately calibrating devices with various metal contacts and gate lengths. Simulations with C-type S/D contacts achieve an $R_{C}$ of $89.6~\Omega $ - $\mu $ m in 7-channel GAA BL $\mathrm {MoS_{2}}$ NS FETs, offering an interesting study for 2D material-based devices.

Keywords

• Source/drain metal contacts
• NS FETs
• density functional theory
• device simulation
• van der Waals gap