Ag adsorption on a single domain Si(001)2 × 1 surface studied by electron and photoelectron diffraction

The initial stages of Ag growth on a single domain (SD) Si(001)2 × 1 surface have been studied by LEED, XPS and X-ray photoelectron diffraction (XPD). It is observed that at room temperature (RT) Ag grows in the Stranski-Krastanov mode with the first layer of ∼ 1 monolayer coverage, with a SD 2 × 1 periodicity but the 1 2 order spots partially elongated. Annealing the RT deposited film to ∼ 80°C results in an intermediate layer with a well-ordered SD c(6 × 2) periodicity. The presence of c(6 × 2) phase has never been reported previously for Ag Si(001). Depositing Ag onto the substrate at ∼ 80°C results in an intermediate layer with a SD 2 × 3 periodicity. The Ag coverages for the SD c(6 × 2) and SD 2 × 3 phases are determined to be the same. XPD shows that the local atomic arrangements of the two SD phases are different in spite of the proximity in coverage and temperature of formation. Annealing the two SD phases to ∼ 300°C results in a transformation into a double domain (DD) 2 × 3 phase with LEED spots partially streaked along the "2 ×" direction. XPS shows no change in Ag coverage for the transformation. Depositing Ag onto substrates at temperatures greater than ∼ 160°C results in the DD 2 × 3 phase.