Low-Temperature Ti-Silicide Forming Reaction in Very Thin Ti-SiO2/Si(111) Contact Systems

Abstract

Very thin (\lesssim4 nm) titanium films were deposited on Si(111) surfaces with very thin (1–4 nm) oxide, SiO₂, layers on top in a UHV system at room temperature. Ti-films with oxygen inclusion did not react at room temperature, but annealing at \lesssim350^°C induced the formation of a TiSi₂ layer between the Ti-film and the SiO₂-layer. On the other hand, Ti-film without oxygen inclusion induced a small but definite SiO₂-reducing reaction at the Ti-SiO₂ interfaces even at room temperature. The amount, or thickness, of the TiSi₂ layers formed between the Ti- and SiO₂-layers could be controlled by varying either the amount of titanium deposited or the annealing temperature.