TEMPLATE STRUCTURE AT THE SILICON AMORPHOUS-SILICIDE INTERFACE/

Surface x-ray diffraction was used to monitor the reaction of Ni on Si (111) at room temperature. Intensity oscillations during deposition si gnify that a layerwise reaction occurs for the first 30 Angstrom of me tal deposited, forming a silicide overlayer with stoichiometry Ni2Si. Structural analysis of the interfacial layers detects an epitaxial and commensurate phase, Ni2Si-theta, with long range order imposed by the substrate but with very large local atomic displacements. This epitax ial structure remains at the interface as amorphous silicide forms abo ve it.