Experimental Evaluation of Coulomb-Scattering-Limited Inversion-Layer Mobility of n-type Metal–Oxide–Semiconductor Field-Effect Transistors on Si(100), (110), and (111)-Surfaces: Impact of Correlation between Conductivity Mass and Normal Mass

Abstract

The inversion-layer electron mobility limited by Coulomb scattering due to interface states (µit) and substrate impurities (µsub) are experimentally evaluated on Si n-type metal–oxide–semiconductor field-effect transistors (MOSFETs) at the surfaces of Si(100), (110), and (111). The inversion-layer mobility is measured by the split C–V method and µit and µsub are extracted using Matthiessen's rule. µit exhibits almost the same behavior irrespective of the different surface orientations, while µsub has the surface orientation dependence. The very weak surface orientation dependence of µit are due to the correlation between the inversion layer thickness (Zave) determined by the normal mass (mz) and the weighed average value of conductivity mass (mc_ave) under multi valley occupation. The surface orientation dependence of µsub is basically explained by the mc_ave difference.