Influence of nitrogen flow rate on microstructural and nanomechanical properties of Zr-N thin films prepared by pulsed DC magnetron sputtering

Zr-N thin films were deposited on Si (1 0 0) substrate by reactive sputtering using a pulsed DC magnetron sputtering technique. It was found that films deposited at 773 K and 1 sccm of nitrogen flow rate show a single phase with face centred cubic-ZrN. Raman analysis also confirmed the formation of ZrN phase in the films. The films deposited at nitrogen flow rate greater than 1 sccm show ZrN along with orthorhombic-Zr3N4. The chemical bonding characteristics of the films were analyzed by X-ray photoelectron spectroscopy. High resolution transmission electron microscopy also gave evidence for fcc-ZrN and o-Zr3N4 phase and revealed equiaxed grains in these films. In addition, hardness and Young's modulus of the films measured as a function of nitrogen flow rate is discussed qualitatively in relation to resistance to plastic deformation offered by these films.