Role of Interfacial and Intrinsic Coulomb Impurities in Monolayer MoS2 FETs

In this work, first, 2D scattering rates in monolayer MoS2 FETs due to interfacial and intrinsic Coulomb impurities as well as all other possible scatterers in an asymmetric dielectric environment have been calculated. Next, using the calculated 2D scattering rates, the electron mobility and current degradation in a monolayer MoS₂ based FET have been studied employing a particle-based quantum-corrected Monte Carlo device simulator. The intrinsic phonon-limited electron mobility is found to be around 10⁵ cm²/V.s. The interfacial effects (remote phonon and remote Coulomb scattering) degrade this value to ~ 36cm²/V.s and intrinsic Coulomb scattering further reduces the electron mobility to ~ 3 cm²/V.s. It is found that Coulomb scattering is responsible for ~ 92% of current degradation, while remote phonon and intrinsic phonon reduce the current by ~33% and ~ 10%, respectively. Among the Coulomb scattering rates, the remote Coulomb scattering from the top oxide (HfO₂) and the bottom oxide (SiO₂) reduce the current by ~ 24% and ~ 72%, respectively. Whereas, the intrinsic Coulomb scattering alone degrades the current by ~90%.