An X-ray photoelectron spectroscopy sputter profile study of the native air-formed oxide film on titanium

• Published in: Applied surface science Vol. 143; no. 1; pp. 92 - 100
• Main Authors: McCafferty, E, Wightman, J.P
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.1999; Elsevier Science
• Subjects: Adsorbed layers and thin films; Atomic, molecular, and ion beam impact and interactions with surfaces; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Impact phenomena (including electron spectra and sputtering); Oxide film; Photoemission and photoelectron spectra; Physics; Titanium; XPS; OC; Oxide film; PG; Titanium; TM; XPS; SP; Thin films; Titanium oxides; Inorganic compounds; Transition element compounds; Experimental study; Depth profiles; Sputtering; X-ray photoelectron spectra
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(98)00927-1

The incipient air-formed oxide film on titanium is approximately 80 Å in thickness and consists of TiO 2. Sputtering the oxide film in vacuum with 3 keV argon ions changes the composition of the oxide film. XPS depth profiles obtained by sputtering with 3 keV argon ions show that after sputtering, the outermost portion of the film consists of TiO 2 and that the inner portion consists of Ti 2O 3 and TiO. Mathematical analysis of the sputtered oxide film as a three-layer structure shows that with increased time of sputtering, the calculated thickness of TiO 2 and its mole fraction in the oxide film decreases faster than that due solely to thinning of the outermost layer. In addition, the mole fraction of the TiO layer increases, while that of the Ti 2O 3 remains relatively unchanged during sputtering. These observations suggest that the ion beam reduces part of the TiO 2 layer to Ti 2O 3, which in turn is then reduced to TiO.