Study of structure development of Titanium Nitride on inclined substrates

For magnetron sputter deposited coatings, the structure development during growth mostly depends on the mobility of the adatom over the substrate. The mobility is significantly affected by the orientation of the substrate with respect to the direction of the incident flux of sputtered atoms. The structural properties like crystallite size, crystallographic structure, column orientation, etc., are therefore influenced. This is relevant as the real work pieces over which the overlay functional coatings has to be applied are three dimensional in nature with the surfaces being off-normal to the incident flux. In the present investigation, the effect of incident angle on the various aspects of the structure development of Titanium Nitride coatings, having wide tribological applications, deposited on Si substrates by reactive magnetron sputter deposition was studied. A planar magnetron, with cathode diameter 75 mm and mounted with pure Ti target was used and TiN was deposited in a mixture of argon and nitrogen gas. The deposition was done for different durations. The deposited coatings were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results indicate the formation of well defined columnar microstructure in the coatings. The column inclination is compared with the well known 'Tangent rule'.