The main objective of this work is the preparation of decorative zirconium oxynitride, $\mathrm{Zr}{\mathrm{O}}_x{\mathrm{N}}_y$ , thin films by dc reactive magnetron sputtering. Film properties were analyzed as a function of the reactive gas flow and were correlated with the observed structural changes. Measurements showed a systematic decrease in the deposition rate with the increase of the reactive gas flow and revealed three distinct modes: (i) a metallic mode, (ii) a transition mode (subdivided into three zones), and (iii) an oxide mode. The measurements of target potential were also consistent with these changes, revealing a systematic increase from $314\text{to}337\mathrm{V}$ . Structural characterization uncovered different behaviors within each of the different zones, with a strong dependence of film texture on the oxygen content. These structural changes were also confirmed by resistivity measurements, whose values ranged from $250\text{to}400\mu \Omega \mathrm{cm}$ for low gas flows and up to ${10}^6\mu \Omega \mathrm{cm}$ for the highest flow rates. Color measurements in the films revealed a change from bright yellow at low reactive gas flows to red brownish at intermediate flows and dark blue for the films prepared at the highest flows. Hardness measurements gave higher values for the region where larger grain sizes were found, showing that the grain growth hardening effect is one of the main parameters that can help explain the observed behavior. Also the peak intensity ratio and the residual stress states were found to be important factors for explaining this behavior.

This work is devoted to the investigation of decorative zirconium oxynitride, $\mathrm{Zr}{\mathrm{O}}_x{\mathrm{N}}_y$ , films prepared by dc reactive magnetron sputtering, using a 17:3 nitrogen-to-oxygen-ratio gas mixture. The color of the films changed from metallic-like, very bright yellow pale, and golden yellow, for low gas mixture flows [from 0 to about $9\mathrm{SCCM}$ (SCCM denotes cubic centimeter per minute at STP)] to red brownish for intermediate gas flows (values up to $12\mathrm{SCCM}$ ). Associated to this color change there is a significant decrease of brightness. With further increase of the reactive gas flow, the color of the samples changed from red brownish to dark blue (samples prepared with 13 and $14\mathrm{SCCM}$ ). The films deposited with gas flows above $14\mathrm{SCCM}$ showed only apparent colorations due to interference effects. This change in optical behavior from opaque to transparent (characteristic of a transition from metallic to insulating-type materials), promoted by the change in gas flow values, revealed that significant changes were occurring in the film structure and electronic properties, thus opening new potential applications for the films, beyond those of purely decorative ones. Taking this into account, the electrical behavior of the films was investigated as a function of the reactive gas flow and correlated with the observed chemical, electronic, and structural features. The variations in composition disclosed the existence of four different zones, which were correlated to different crystalline structures. For the so-called zone I, x-ray diffraction revealed the development of films with a B1 NaCl face-centered cubic zirconium nitride-type phase, with some texture changes. Increasing the reactive gas flow, the structure of the films is that of a poorly crystallized overstoichiometric nitride phase, which may be similar to that of ${\mathrm{Zr}}_3{\mathrm{N}}_4$ , but with some probable oxygen inclusions within nitrogen positions. This region was characterized as zone II. Zone III was indexed as an oxynitride-type phase, similar to that of $\gamma \text{‐}{\mathrm{Zr}}_2\mathrm{O}{\mathrm{N}}_2$ with some oxygen atoms occupying some of the nitrogen positions. Finally, occurring at the highest flow rates, zone IV was assigned to a $\mathrm{Zr}{\mathrm{O}}_2$ monoclinic-type structure. The composition∕structure variations were consistent with the chemical bonding analysis carried out by x-ray photoelectron spectroscopy, which showed oxygen doping in both ${\mathrm{Zr}}_3{\mathrm{N}}_4$ - and ZrN-type grown films. The electronic properties of the films exhibited significant changes from zone to zone. Resistivity measurements revealed a very wide range of values, varying from relatively highly conductive materials (for zone I) with resistivity values around few hundreds of $\mu \Omega \mathrm{cm}$ to highly insulating films within zones III and IV, which presented resistivity values in the order of ${10}^{15}\mu \Omega \mathrm{cm}$ . Regarding zone II, corresponding to oxygen doped ${\mathrm{Zr}}_3{\mathrm{N}}_4$ -type compounds, the observed behavior revealed resistivity values increasing steeply from about ${10}^3$ up to ${10}^{15}\mu \Omega \mathrm{cm}$ , indicating a systematic transition from metallic to insulating regimes.