Hydrogen mediated transport of Sn to Ru film surface

The authors report on the interaction of atomic hydrogen with Sn and thin Ru film at room temperature. The study is done using a combination of photoelectron and low energy ion scattering spectroscopies as well as scanning electron microscopy. The adsorption of hydrogen on a Sn surface leads to the formation of stannane ( SnH 4 ) , which dissociatively adsorbs on the surface of polycrystalline Ru film. In the range of effective Sn coverages studied (up to 1 ML), the resulting overlayer consists of randomly distributed three-dimensional islands with average size below 40 nm occupying up to several percent of the surface area. Nucleation of Sn is observed presumably at defect sites (e.g., grain boundaries). Ion scattering data are found consistent with Volmer–Weber growth mode: no initial transition wetting layer formation is detected. Oxidation of Sn islands on a Ru surface at room temperature results in the formation of SnO. Neither metallic nor oxidation states of Sn higher than Sn 2 + are observed by photoelectron spectroscopy.