An EXAFS and XRD Study of the Structure of Nanocrystalline Ti-B-N Thin Films.

The structure of sputter deposited Ti-B-N thin films of three different compositions has been investigated using glancing angle XRD, EXAFS and NEXAFS. The chemical composition of the films was established by XPS and the equilibrium phase composition was calculated from an established phase diagram for the bulk Ti-B-N system. For the Ti-B-N layers low in nitrogen we found a nanocrystalline TiB2 type structure in accordance with the predictions of the phase diagram. However, for a nitrogen rich layer with the composition Ti-B1.7N1.8 the expected Ti containing phases, principally TiN, did not appear to be well formed. For this layer, the local structure around the central Ti atoms as deduced by EXAFS showed the Ti atoms mainly to be situated in disordered regions, possibly extremely small Ti/B or Ti/N clusters with no long range crystalline order.JRC.(IAM)-Institute For Advanced Material