Effect of Oxygen Doping on the Structure of TiN Surface Coatings

Abstract

In the present work the influence of the level of oxygen doping on the structure of TiN films was investigated by dedicated experiments. The films were deposited at 400°C in an all metal UHV device by unbalanced magnetron sputtering at the same Ar and nitrogen flow rates, but the oxygen flow rate was changed in the experiments, incorporating oxygen in the range of 4 and 20 at.%. The structure of the films was investigated by XRD, Auger electron (AES) and X-ray photon electron (XPS) spectroscopy and transmission electron microscopy (TEM). The results discovered the crystal face anisotropy in the incorporation-segregation of oxygen leading to the change of the <111> texture to <002>. The structure analysis revealed that the <002> texture is developing also by competitive growth of crystals, which is the result of the limitation of the growth of the <111> oriented crystals by the TiO 2 layer developing on their growth surface by the segregated oxygen species. The oxygen incorporating in the crystal lattice on the 002 crystal faces of the <002> oriented crystals is segregated by surface spinodal decomposition, developing nm sized 3D TiO-2 inclusion both in the bulk of the columns and the column boundaries.