Impact of different gate insulator materials on the electron mobility in ultra-thin (100) InGaAs-on-insulator MOS devices

In this paper, we studied the influence of the parameters of technologically relevant dielectrics (SiO₂, Al₂O₃ and HfO₂) and channel thickness downscaling on the electron mobility in InGaAs-on-insulator channels with (100) surface orientation. The study of mobility properties is enabled by a self-consistent Schrödinger-Poisson solver that is coupled with a scattering simulator based on the momentum relaxation time approximation, in order to calculate the scattering rates of electrons with acoustic, optical, remote and polar phonons, surface roughness, Coulomb impurities and alloy disorder. Simulations revealed that SiO₂ is the optimum gate dielectric material irrespective of the body thickness, followed by Al₂O₃ or HfO₂, depending on InGaAs-to-oxide surface roughness.