Monte Carlo study of surface roughness scattering in Si inversion layer with improved matrix element

The electron mobility in the inversion layer of metal oxide semiconductor field-effect transistors was calculated by using a Monte Carlo method. We utilized an improved matrix element for accurately calculating the surface roughness scattering among the many factors determining the electron mobility. The improved matrix element employed different effective electric fields ( E eff ) for each subband energy level. From the simulation results, we demonstrated that the relative proportion of surface roughness scattering was about three times greater than that of acoustic phonon scattering at an electric field of 1 MV ∕ cm . In particular, the electron mobility curve calculated with the improved matrix element showed better consistency with universal experimental data as compared to a curve calculated with a conventional matrix element.