Formation of (113) texture in fcc nitride thin films and its influence on the film properties
This work presents a study of XRD measurements on the development of the (113) preferential orientation with film thickness for Ti0.67Al0.33N films grown on Si(100) substrates by pulsed DC magnetron sputtering. The buildup of (113) texture was observed using both theta-2 theta scans and pole figure XRD techniques that are in contrast to the commonly observed formation of the (111) orientation. Three regimes of texture growth have been determined to lead to the microstructural evolution and textural development of (113) in Ti0.67Al0.33N by minimizing the total energy of the film. The first regime is characterized by small crystallites preferentially growing in < 002 > direction; the second involves the development of (111) crystallites associated with the competitive growth mechanism, as well as tilting of (002) planes to let the < 111 > orientation remain parallel to the film normal. In the third regime, we have found that to minimize the total energy of the system, the orientation of the growing film switches from (111) to (113) with preferentially less density that causes a decrease in hardness and stress formed in the (111)-oriented grains. The surface topography of the coatings was studied using scanning electron microscopy (SEM). Different mechanisms which could explain the crossover of (002), (111), and (113) orientations through film thickness are discussed. Development of the (113) orientation is examined with respect to stress, morphology and mechanical properties. (c) 2012 Elsevier B.V. All rights reserved.