Titanium diboride thin films produced by dc-magnetron sputtering: Structural and mechanical properties

The use of titanium diboride films as protective coatings was proposed for several applications because of its mechanical and tribological properties, as well as chemical and thermal stabilities. The aim of this work is to evaluate the effects of the deposition parameters on the microstructure and mechanical properties of titanium diboride films. All films were deposited on silicon substrates by dc-magnetron sputtering from a stoichiometric TiB2 target in argon atmospheres. The chemical composition was determined by Rutherford backscattering spectroscopy (RBS), while structural information was obtained by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The intrinsic stress of the films was determined by measuring the change of the substrate curvature due to film deposition. Surface roughness was studied by Atomic Force Microscopy (AFM). The film hardness and elastic modulus were determined by nanoindentation measurements. The correlation between the mechanical properties with the film density is presented. The internal stress reduction occurs with substantial reduction of the film hardness, and it occurs for films with low mass density.