On the correlation between surface roughness and inversion layer mobility in Si-MOSFETs

A quantitative analysis of the Si/SiO2 interface roughness based on atomic force microscope (AFM) and mobility measurements is presented. Our results show that the spatial components of the roughness affecting the carrier transport lie outside the range probed by AFM, thus making questionable the validity of previously published correlations between AFM measurements and carrier mobility, Based on a numerical model of the roughness scattering, a new physically-based correlation is proposed, highlighting the impact, so far overlooked, of the roughness correlation length an the carrier mobility.