Improving contact resistance in MoS2 field effect transistors

Abstract

MoS₂ is a material of interest for two-dimensional (2D) field effect transistors (FETs) [1-3], however contact resistance (R_c) remains a key limiting factor. Here we present a systematic study of contact resistance to MoS₂ using various metals with different deposition conditions, compared to detailed simulations. We find that decreasing the metal deposition pressure improves the metal-MoS2 interface and brings R_c for Au contacts to <;1 kΩ-μm, which is lower than previous reports with Ni, Sc, or Au [1,4]. Comparison to simulations suggest that while the contact resistivity is reasonably good (ρc ≈ 5·10^-7 Ω·cm²), the lateral access resistance limits Rc in MoS₂ FETs. This study is crucial for scalability of MoS₂ devices, also suggesting methods to further improve Rc.