Investigation of the crystal structure on the nanomechanical properties of pulsed laser deposited niobium nitride thin films

NbN thin films grown on Nb using pulsed laser deposition (PLD) were investigated for film crystal structures. The nanomechanical properties of NbN on Nb were examined as a function of the film/substrate crystal structure. X-ray diffraction (XRD) reveals peaks that correspond to δ-NbN cubic and β-Nb2N hexagonal phases in addition to δ′-NbN phase. Samples of various crystal structures were tested for phase characterization, microstructure, and surface morphology using XRD analysis, scanning electron microscopy, and atomic force microscopy. The nanomechanical properties were investigated using nanoindentation. The results indicate that there are clear effects of the crystal structure on the hardness of the PLD-grown NbNxfilms.