Activated metal deposition and oxide growth on semiconductors: TiO2/Si(111)-2×1

Abstract

We report a high-resolution x-ray photoemission study of interface formation involving 1–30 Å of TiO2 grown on p-type Si(111)-2×1 by the deposition of Ti in an activated oxygen atmosphere (5×10−6 Torr). Line-shape analysis for the Si 2p, Ti 2p, and O 1s core levels and the valence bands indicates that the Ti adatoms are in the formal 4+ oxidation state in TiO2, that a thin Si oxide interlayer also forms at the interface but is uniformly covered by TiO2, and that Ti–Si reaction is suppressed. For low TiO2 coverages, we observe a nonmonotonic movement of the semiconductor Fermi level.