Compact Model of Carrier Transport in Monolayer Transition Metal Dichalcogenide Transistors

Monolayer 2-D transition metal dichalcogenide (TMDC) field-effect transistors (FETs) have excellent scaling properties due to an extremely thin body and reduced quantum-mechanical tunneling. High-field and ballistic carrier transport can play an important role in aggressively scaled TMDC FETs. A compact model is developed to describe carrier transport in 2-D monolayer FETs based on a TMDC material. The model has the following features: 1) it treats high-field transport and velocity saturation; 2) it can be applied from ballistic to quasi-ballistic to diffusive transport regimes; and 3) it incorporates analytical expressions for carrier mobility values based on examining physical carrier scattering mechanisms in TMDC materials. Monte Carlo simulation, which solves the Boltzmann transport equation stochastically, is used to validate the model. The carrier transport model is further integrated with a virtual-source model to calculate the ${I}$ – ${V}$ characteristics of 2-D monolayer FETs. Based on the model, the effects of phonon scattering and ionized impurity scattering on the average carrier injection velocity and transistor ballisticity are discussed.