Diffusion-layer microstructure of Ni on Si(100)

Abstract

The initial stage of nickel silicide compound formation at Si(100) surfaces is investigated using low-energy electron diffraction and ultraviolet photoemission spectroscopy. Experimental evidence is obtained for the postulated high interface mobility resulting from transforming the bonding of interface Si atoms from covalent to metallic character. The bond transformation is induced by nickel atoms occupying tetrahedral interstitial voids of the Si lattice. The observed interstitial Ni $d$-state binding energy suggests a diffusion-layer microstructure which does not favor nickel-atom occupancy of adjacent tetrahedral voids.