Structure studies of oxygen buried layers in titanium by synchrotron X-ray scattering

Thin buried layers of titanium oxides have received great attention due to their possible use for optoelectronic components and as a diffusion barrier in semiconductor technology. Ion implantation is a very versa-tile method to produce such buried layers whereas the physical properties of the oxide in the host matrix can be tailored by the variation of e.g. the implan-tation temperature and/or the fluence. The structure and phase transformation in such buried im-plan-ted layers were not investigated in details up to now.
The contribution reports an investigation of buried layers fabricated by means of high-fluence (10 17…10 18 cm-2) oxygen ion implantation into titanium. The implantation was performed at an energy of 200 or 450 keV, leading to a buried implanted profile in a depth of 270 nm or 600 nm, respectively.
The structure of the buried layers was examined by different X-ray diffraction (XRD) techni-ques at a standard diffractometer and with synchrotron radia-tion at the Rossendorf Beamline at ESRF. The elemental composition of the implanted samples was studied by Auger electron spectroscopy. The microstructural properties of modified near-surface titanium and oxygen buried layers were investigated as a function of the ion energy, the fluence and the influence of post-annealing treatment. Structural changes in the titanium lattice due to an increase of oxygen content and formation of Ti3O (or Ti6O) (with oxygen content up to 30 at.%) were found. Depending on the implantation fluence a phase transition process in the buried layers of a-Ti - Ti3O (or Ti6O) - TiO was detected.