COMPUTATIONAL INVESTIGATION OF TWO-DIMENSIONAL DIELECTRIC MATERIALS FOR MOS₂-BASED FIELD-EFFECT TRANSISTORS

In the pursuit of improved performance, smaller products and denser designs, the microelectronics industry has seen a rapid downscaling in size. Key to this evolution is the continuous miniaturization of the Field-Effect Transistor (FET). Traditionally, FETs are based on bulk (3D) materials, which have thus far been successfully scaled down to the nanoscale dimension. However, this reduction in size is limited due to current leakage and other short-channel effects which are detrimental to the FET’s operation. To facilitate the continued scaling-down of the FET while further improving its performance, many new approaches have been implemented. In this aspect, two dimensional (2D) materials have aroused immense interest.
A notable semiconducting candidate among 2D materials is Molybdenum Disulfide (MoS₂), which has proven to be advantageous for suppressing current leakage in ultra-short transistors at the scaling limit and offers superior immunity to short-channel effects. However, the charge-carrier mobility in a MoS₂ channel has proven to be highly dependent on its dielectric surroundings and initial MoS₂ devices showed a reduction in intrinsic properties due to adverse interactions with SiO₂, the traditional insulating material in FETs. In my research, I study potential 2D materials for use in 2D-MoS₂-based FETs.
The structure and properties of the materials in question are determined through Density Functional Theory (DFT) calculations. DFT is a method of obtaining a material’s electronic ground state from its electron density distribution. From the electronic ground state, various chemical and physical properties of the material related to transistor performance can be investigated.