Improving contact resistance in MoS<inf>2</inf> field effect transistors

Abstract

MoS2 is a material of interest for two-dimensional (2D) field effect transistors (FETs) [1-3], however contact resistance (R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> ) 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 <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> 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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−7</sup> Ω·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ), the lateral access resistance limits Rc in M0S2 FETs. This study is crucial for scalability of MoS2 devices, also suggesting methods to further improve Rc.