Abstract
Zirconium nitride (ZrN) thin films have good corrosion and wear resistance in the aggressive environment for decorative coating. The narrow range of golden yellow color could limit the application of ZrN films in decorative coatings. By introducing the oxygen flow during coating, we can obtain zirconium oxynitride thin films which have good mechanical properties, chemical inertness, and have various colors from golden yellow to dark blue. Zr(N,O) films were deposited on P-type Si(100) wafer using hollow cathode discharged ion-plating (HCD-IP) by changing O2 flow rate from 0 to 8 sccm and deposition time from 14 to 56 min based on our previous study. The coloration of Zr(N,O) film attributing to intrinsic or extrinsic was studied. Effect of thickness and other composition, structure, and properties of Zr(N,O) thin films were characterized. The oxygen content of the thin film, determined using X-ray photoelectron spectroscopy (XPS), increased with increasing oxygen flow rate, meantime it decreased with incresing thickness. The phase separation of ZrN, Zr2ON2 and ZrO2 was indicated by using X-ray diffraction and XPS analysis. The coloration of specimens prepared at 0, 3, and 5 sccm O2 flow rate was intrinsic but that of 8 sccm samples showed the characteristic of extrinsic color. The film hardness increased with increasing thickness. The resistivity increased with decreasing thickness; however, the effect of oxygen content on resistivity was more significant than film thickness of pure ZrN thin films. No significant change of the residual stress measurement by the optical method with thin thickness was noted. Finally, Poisson’s ratio and elastic constant of ZrN thin film were calculated by combining the results of modified sin2ψ XRD method and optical measurement.