Study of Thickness-Dependent Mobility of MoS2FETs with HfO2 Encapsulation by Edge Contact

Back-gate molybdenum disulfide (MoS₂) field effect transistors (FETs) are very sensitive to thickness of channel material because of weak dielectric screening and strong interlayer coupling in multilayer Mos₂. In this paper, we utilize soft Argon (Ar) plasma to pattern Mos₂ to make edge contact to Mos₂. Then, the Mos₂ flake on SiO₂/Si substrate is coated with 30 nm HfO₂ using ALD to get the Hfo₂/MoS₂/SiO₂ heterostructure. Experimental results show that the carrier mobility of 9 nm Mos₂ back gate FET is up to 38 cm²/(V*s) at room temperature.