Reactivity of intermetallic thin films formed by the surface mediated decomposition of main group organometallic compounds.

We have observed that by the reaction of silane with clean Ni, Rh, Pt, Mo, Ta, W, Cu, and Au surfaces at elevated temperatures, thin alloy and intermetallic compound phases can be prepared. For example, SiH4 reacts with atomically clean nickel surfaces to give a > 50 angstrom surface film of predominantly Ni2Si. Subsequent reaction with oxygen leads to the formation of a thin passivating layer of SiO2; structurally similar materials were also obtained from the direct reaction of silane with oxidized nickel surfaces. Our results from studies on a wide variety of metal surfaces suggest a general procedure for the preparation of passivating, non-native oxide thin films.