Evaluation of chemical structure and Si segregation of Al/Si(111)

Abstract Control of diffusion and segregation of Si atoms through a thin metal layer from a stacked Si structure is one of the effective techniques to grow two-dimensional (2D) or ultrathin Si crystals. We have studied the formation of the Al layer with a flat surface and high crystallinity on a wet-cleaned Si(111) wafer by thermal evaporation in order to use it as a growth template for ultrathin Si crystals. Then, the impacts of the annealing in N 2 ambient on the surface flatness, the Al crystallinity, and the chemical bonding features for the Al/Si(111) structure were investigated. A formation of a sub-nanometer Si layer on the Al(111) surface using Si segregation with keeping surface flatness was demonstrated by the control of annealing temperature.