Metal/silicon reactions studied by high energy ion scattering

The initial stages of the metal/silicon reactions have been investigated for Au, Ag, Pd/Si(111) and Au, Ag/Si(001) systems with film thicknesses less than ∼ 15 ML (1 ML ∼ 7 x 1014 atoms/cm2) using a MeV ion scattering/channeling technique. In addition to single metal depositions, sequential depositions of two different metals were performed. In the former case, obvious differences in the reactivities at the interfaces were observed for the Au/Si, Pd/Si (reactive) and Ag/Si systems (little reactive). Sequential depositions of Au and Ag brought forth interesting results. Predeposited Au of < approx 2 ML enhanced displacements of Si during subsequent Ag depositions, irrespective of the substrate orientations. The interfacial reactions of the noble metal(s)/Si and the Pd/Si systems are discussed in relation to the damage cross section of Si crystal atoms near the interfaces. (author)