Chemical reactions at surfaces: titanium oxidation

Auger electron spectroscopy has been used to study the first stages of tita nium oxidation. Titanium at room and high temperature, as well as thin film s deposited over a metal substrate, were oxidized at low pressure. The auth ors found, using factor analysis, two different regimes depending on the sa mple temperature. For temperatures below 200 degrees C the oxidation is cha racterized by the presence of only one oxide phase: TiO2. At higher tempera tures, the presence of Ti2O3 is detected from the beginning of the process. For thin films [less than one monolayer (ML)] only TiO2 was found, but for thicker films a new oxide phase is detected (TiOx, x<2). Finally, for thic knesses >7 ML, only TiO2 is detected. (C) 1999 Elsevier Science S.A. All ri ghts reserved.