Determination of Si/SiO2 interface roughness using weak localization

The authors have measured the interface roughness of intentionally textured Si/SiO₂ interfaces using the quantum weak localization correction to the electrical conductivity at low temperatures. The deduced roughness was confirmed by observation of the Si surface replicas by atomic force microscopy. Channel electron mobility measurements at 4.2, as well as theoretical calculations, indicate that long length-scale roughness may have little or no impact on the mobility. An appropriate choice for the length scale of morphology measurements must therefore be made when correlating with mobility.