Grain-size effect on the preferred orientation of TiC/α-C:H thin films

The grain-size effect on the preferred orientation was revealed in TiC/α-C:H nanocomposite films grown by magnetron sputtering, in which the grain size of TiC can be adjusted through changing C content in the films. The finding showed that the preferred orientation of the films was significantly affected by the grain size, and the crystallographic orientation changed from face-centered cubic (fcc) TiC (111) to (200) as the grain size of nanocrystallite TiC decreased from about 22.3 to about 4.7nm. This size-dependent preferred orientation was explained via thermodynamic calculations, from which the size-dependent Gibbs free energies were found to be a key factor that controled the texture development in the thin films if grain size in the films was sufficient small.