Stoichiometry and thickness of the initial oxide formed on clean titanium surfaces determined by quantitative Auger electron spectroscopy, electron energy loss spectroscopy, and microgravimetry

The initial oxidation of a clean polycrystalline titanium film was studied by Auger electron spectroscopy (AES) and electron energy loss spectroscopy (ELS), while simultaneously monitoring the total oxygen uptake using the quartz crystal microbalance (QCM). Quantitation of the OKLL and TiLMM AES intensities reveals that the surface stoichiometry at the initial stages of oxidation (<100LO2at 1X 10“5Torr) corresponds to that expected for Ti203, and the ELS results also suggest the presence of the lower oxidation states of titanium ( + 2, + 3) on the surface. The microgravimetric results indicate that the oxidation is not confined to the region sampled by the electron spectroscopic methods, and a surface layer of Ti203 whose thickness is — 40 A is consistent with the observed combination of results.