Optical Properties and Elemental Composition of Ta2O5 Thin Films

The optical properties of tantalum oxide thin films fabricated by electron beam evaporation with ion assisted have been investigated. The as-deposited thin films are of good transmittance, of which the maxima is about 93%, close to that of the bare substrate; the refractive indexes are found to increase with the substrate temperature. The elemental composition and chemical bonding state in the as-deposited thin film has also been probed by X-ray photoelectron spectroscopy (XPS). The XPS results reveal that the main composition of the as-deposited film is mainly Ta₂O₅ with some TaO_x and a little TaO, the O/Ta ratio is about 2.69 which is a bit higher than the stoichiometry of Ta₂O₅.