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Dc reactive magnetron sputtering was implemented to successfully deposit Ti(C,O,N) thin films on polymer, glass and silicon. A Ti target with C incrusted pieces was sputtered while a mixture of oxygen and nitrogen was injected into the deposition chamber. The main aim of this paper was to study the influence of the (O2 + N2) flow rate on the structure and on the mechanical and electrical properties of titanium oxycarbonitride thin films. These results were compared to pre-existing knowledge about sputtered Ti-O-N and Ti-C-O films, tailoring their properties between those of TiN (or TiC) and TiO2 coatings. Moreover, some attention was especially focused on the adhesion of the Ti(C,O,N) coatings on polymer.
The available knowledge on multifunctional materials based on a quaternary system is still very weak. In this sense, tuning the oxygen / (nitrogen + carbon) ratio allowed obtaining a large spectrum of different properties and can be considered as a step forward to a better understanding of this kind of materials.
Composition analysis by Rutherford backscattering analysis (RBS) was done to quantify the titanium and metalloid concentrations in the films. X-ray diffraction (XRD) results were carried out to determine the crystallographic structure and were correlated to the mechanical properties of the films. This paper started answering to the weak knowledge on the Ti(C,O,N) structure. Then a theoretical investigation on their structural and mechanical properties was led using ab-initio calculations based on Density Functional Theory (DFT). Two simulation models, based on the incorporation of oxygen into a TiC and a TiO crystalline structure, were applied. Calculated and experimental lattice parameters and elastic constants were in good agreement. The evolution of the electrical conductivity of the films was analyzed as a function of mechanical damage of the polymer substrate. An accurate control of the reactive gas mixture flow rate was also successfully obtained in order to obtain one intrinsic, stable and attractive color. For that, the color was characterized by spectral reflectance spectroscopy, and expressed in the CIE 1976 L*a*b* color space. |