Surface structures of Si deposited on W(110) surface

Abstract We have investigated the surface structure of Si films deposited on W(110) surfaces by reflection high energy electron diffraction. Si films thinner than 4.5 A exhibited the [ 2 1 0 2 ] structure in the temperature range from room temperature to 500°C, which is consistent with the results of FIM experiments reported by Tsong et al. Seven new surface structures were observed at temperatures ranging from 700°C to 1200°C for various film thicknesses and a phase diagram for two-dimensional surface structures was constructed. In general, the surface structure changed from one phase to another phase as the substrate temperature gradually increased. However, when the structure changed from [ 9/2 4/7 0 8/7 ] to [ 9/2 7/12 0 7/6 ] above 1130°C, the unit mesh continuously stretched along the W [1 1 0] direction, resulting in a gradual increase in the distance between adjacent two Si atoms along the W[1 1 0] direction on the W substrate from 2.56 to 2.61 A with increasing temperature. For each surface structure, the unit mesh was determined precisely by analyzing not only single scattering reflections, but also multiple scattering reflections.