OXIDATION PROCESS IN TITANIUM THIN-FILMS

The first stages of the oxidation process of titanium thin films depos ited on top of Cu(100) substrates have been studied by means of Auger electron spectroscopy. Using principal component analysis we found dif ferent oxidation regimes for Ti films depending on their thickness. Wh ile for a film thickness up to 1 ML only one oxide phase (TiO2) is pre sent, in thicker films a new oxide phase (TiOx; x<2) is detected. As t he Ti film grows, the passivating effect of the titanium oxide stops t he process of oxygen adsorption. Finally, for the thickest films (>7 M L) the effect of the interface turns out to be negligible and the oxid ation characteristics of bulk titanium are recovered; i.e., only TiO2 is detected again.