Stress, phase stability and oxidation resistance of ternary Ti–Me–N (Me=Zr, Ta) hard coatings

• Published in: Thin solid films Vol. 538; pp. 56 - 70
• Main Authors: Abadias, G., Koutsokeras, L.E., Siozios, A., Patsalas, P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2013; Elsevier
• Subjects: Chemical thermodynamics; Chemistry; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; General and physical chemistry; Magnetron sputtering; Other nonelectronic physical properties; Physical properties of thin films, nonelectronic; Physics; Stress; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermal annealing; Thermal stability; thermal effects; Thermodynamic properties; TiTaN; TiZrN; Transition metal nitrides; TiZrN; Magnetron sputtering; TiTaN; Thermal annealing; Stress; Transition metal nitrides; Field emission; XRD; Thin films; Nitrides; Cathode sputtering; Monte Carlo methods; Wafers; Physical vapor deposition; Titanium; Stress effects; Oxidation; Phase stability; Thermal stresses; Grain size; Scanning electron microscopy; Vacuum annealing; Stress analysis; Grain growth; Grain orientation; Layer thickness; Preferred orientation; Reflectivity; Thermal properties; Compressive stress; Morphology; Transition elements; Growth mechanism; Sputter deposition; Thermodynamic properties; Curvature; Hard coating; X-ray photoelectron spectra
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2012.10.119

In this work, we comparatively study the phase formation, stress development, thermal stability and oxidation resistance of two ternary transition metal nitride systems, namely Ti–Zr–N and Ti–Ta–N, in the whole compositional range. Thin films, with thickness up to 300nm, were synthesized by reactive magnetron sputter-deposition in Ar+N2 plasma discharges at 300°C from elemental metallic targets. The energy distribution of energetic species is considered based on Monte-Carlo simulations (SRIM+SIMTRA codes). The origin of stress build-up during growth is addressed by combining in situ wafer curvature and ex situ X-ray diffraction (XRD) techniques. For as-deposited films, a unique dependence of growth morphology, grain size, preferred orientation and compressive stress evolutions on growth energetics is revealed, independently of the system. The phase stability upon vacuum and air annealing up to 850°C was followed using in situ temperature XRD, ex situ X-ray Photoelectron Spectroscopy and optical reflectivity, while the morphological evolution was characterized using field emission scanning electron microscopy. ► Ti–Zr–N and Ti–Ta–N sputtered thin films are comparatively studied. ► Growth energetics is shown to govern stress, texture and morphology. ► The solubility range of Zr in cubic TiN lattice is larger than for Ta. ► Stress relaxation was the main structural change after vacuum annealing at 850°C. ► Ti–Ta–N films showed superior oxidation resistance in air compared to Ti–Zr–N.