Effects of orientation on microstructure and mechanical properties of TiN/AlN superlattice films

Superlattice structure can significantly improve the hardness of the films without damaging the toughness. However, in TiN/AlN superlattice structure, the thickness of metastable c-AlN has a certain limit, which limits the improvement of hardness. We adjusted the orientation of the entire superlattice films under the same deposition parameters and observed that AlN has a thicker coherent thickness in the -oriented TiN/AlN superlattice film relative to the orientation through HRTEM, and the superlattice film reached a higher hardness peak value (~38.6GPa) at the same time. This work provides a new implementation method to improve the mechanical properties of superlattice films.