KEY ISSUES IN USING TWO-DIMENSIONAL TRANSITION-METAL DICHALCOGENIDES FOR TRANSISTOR APPLICATIONS

Abstract

Two-dimensional transition-metal dichalcogenides (TMDs) are one family of prospective channel materials that can be used in future transistors, but a number of challenges need to be addressed so that the fabrication of TMD transistors is compatible with the manufacturing processes in the semiconductor industry. In this thesis, we aim to address two key issues that impedes the adoption of TMDs in transistor applications: spatial control of doping and deposition of ultrathin high-k dielectrics. To lower the energy barrier in doping, we systematically study the selective generation of S defects in MoS2 without degrading the sample quality using low-energy plasma. We further study p-doping of intrinsically n-type TMDs by incorporating nitrogen into the defect sites, which can effectively reduce the thermal budget. Finally, we show that the uniformity and interface quality of ultrathin Al2O3 films deposited on MoS2 by atomic layer deposition can be improved via a water plasma pre-treatment.