The room temperature growth of Ti on sputter-cleaned Si(1Â 0Â 0): Composition and nanostructure of the interface

The formation of the interface during the deposition of titanium on sputter-cleaned Si(1 0 0) substrates has been studied at room temperature using X-ray photoelectron spectroscopy (XPS), angle resolved XPS (ARXPS), ultraviolet photoelectron spectroscopy (UPS) and ion scattering spectroscopy (ISS). The experimental results are consistent with a two-stage mechanism for Ti growth: a first stage characterized by the formation of a uniform layer ∼4 monolayer (ML) thick of TiSix (x ≈ 0.78), followed by a second stage in which metallic Ti grows over the titanium silicide formed previously. During the second stage, metallic Ti grows according to a Stranski-Krastanov mechanism, with the formation of a Ti monolayer followed by the growth of metallic titanium islands with an average thickness of 7 ML. The formation of a titanium silicide during the first stage of growth, involves charge transfer from Ti to Si.