Comparison between oxygen depth profiles in oxygen-implanted titanium measured by RBS and XPS combined with argon sputtering

Abstract

Abstract A study has been made of composition, structure and chemical state of oxygen-implanted titanium by means of Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) combined with argon sputtering. Oxygen molecule ion implantation in titanium was performed with fluences of (3−10) × 10 17 ions/cm 2 at 150 keV at room temperature. In the case of highest fluence, XPS results showed that the oxygen depth profile was trapezoidal and the atomic ratio of O/Ti at the flat-topped plateau was about 1.5. This value is lower than the value of 2 implied from the formation of TiO 2 (rutile) as deduced from XRD patterns. RBS results showed that the oxygen depth profile was also trapezoidal and the atomic ratio of O/Ti was about 2. The lower atomic ratio of O/Ti obtained by XPS as compared to XRD and RBS may be caused by preferential sputtering of oxygen during argon bombardment of XPS measurements. In conclusion, it is expected by XPS and XRD and confirmed by RBS that high-fluence oxygen implantation in titanium forms a trapezoidal distribution of oxygen with a stoichiometric ratio of TiO 2 at a flat-topped plateau.