title: The competitive growth of cubic domains in Ti(1-x)AlxN films studied by diffraction anomalous near-edge structure spectroscopy.
abstract: Titanium and aluminium nitride films deposited by magnetron sputtering generally grow as columnar domains made of oriented nanocrystallites with cubic or hexagonal symmetry depending on Al content, which are embedded in more disordered grain boundaries. The substitution of Al atoms for Ti in the cubic lattice of the films improves their resistance to wear and oxidation, allowing their use as protective coatings. Ti K-edge X-ray absorption spectroscopy, which probes both crystallized and more disordered grain boundaries, and X-ray diffraction anomalous fine structure, which is sensitive to short- and long-range order within a given crystallized domain, are carried out on a set of Ti(1-x)AlxN films deposited by magnetron sputtering on Si substrates. Attention is paid to the shape of the pre-edge region, which is sensitive to the symmetry of the site occupied by Ti atoms, either octahedral in face-centred-cubic Ti-rich (TiN, Ti0.54Al0.46N) samples or tetrahedral in hexagonal-close-packed Al-rich (Ti0.32Al0.68N) films. In order to obain information on the titanium environment in the well crystallized areas, subtraction of the smooth part of the energy-dependent structure factor for the Bragg reflections is applied to the pre-edge region of the diffraction anomalous data in order to restore their spectroscopic appearance. A flat pre-edge is related to the typical octahedral environment of Ti atoms for cubic reflections. The difference observed between pre-edge spectra associated with face-centred-cubic 200 and 111 Bragg reflections of Ti0.54Al0.46N is assigned to Ti enrichment of 111 large well ordered domains compared with the more disordered 200 ones. The sharp peak observed in the spectrum recorded from the hexagonal 002 peak of Ti0.32Al0.68N can be regarded as a standard for the pure tetrahedral Ti environment in hexagonal-close-packed nitride.
authors.affiliation: Université de Haute-Alsace, Laboratoire de Physique et Mécanique Textiles (EA 4365), Equipe Propriétés Physiques et Mécaniques des revêtements, 61 rue Albert Camus, F-68093 Mulhouse, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Pinot
authors.affiliation: Université de Haute-Alsace, Laboratoire de Physique et Mécanique Textiles (EA 4365), Equipe Propriétés Physiques et Mécaniques des revêtements, 61 rue Albert Camus, F-68093 Mulhouse, France.
authors.forename: M-H
authors.initials: MH
authors.lastname: Tuilier
authors.affiliation: Université de Haute-Alsace, Laboratoire de Physique et Mécanique Textiles (EA 4365), Equipe Propriétés Physiques et Mécaniques des revêtements, 61 rue Albert Camus, F-68093 Mulhouse, France.
authors.forename: M-J
authors.initials: MJ
authors.lastname: Pac
authors.affiliation: Université de Franche-Comté, Franche-Comté Electronique, Mécanique, Thermique et Optique - Sciences et Technologies (UMR CNRS 6174), BP 71427, F-25211 Montbéliard, France.
authors.forename: C
authors.initials: C
authors.lastname: Rousselot
authors.affiliation: Synchrotron Soleil, Saint Aubin, F-91192 Gif sur Yvette, France.
authors.forename: D
authors.initials: D
authors.lastname: Thiaudière
keywords: X-ray absorption fine structure; X-ray diffraction; diffraction anomalous fine structure; metallic nitride film