Ternary transition metal nitride thin films, with thickness up to 300 nm, were deposited by dc reactive magnetron cosputtering in Ar–N2 plasma discharges at 300 °C on Si substrates. Two systems were comparatively studied, Ti–Zr–N and Ti–Ta–N, as representative of isostructural and nonisostructural prototypes, with the aim of characterizing their structural, mechanical, and electrical properties. While phase-separated TiN–ZrN and TiN–TaN are the bulk equilibrium states, Ti1−xZrxN and Ti1−yTayN solid solutions with the Na–Cl (B1-type) structure could be stabilized in a large compositional range (up to x=1 and y=0.75, respectively). Substituting Ti atoms by either Zr or Ta atoms led to significant changes in film texture, microstructure, grain size, and surface morphology, as evidenced by x-ray diffraction, x-ray reflectivity, and scanning electron and atomic force microscopies. The ternary Ti1−yTayN films exhibited superior mechanical properties to Ti1−xZrxN films as well as binary compounds, with hardness as high as 42 GPa for y=0.69. All films were metallic, the lowest electrical resistivity ρ∼65 μΩ cm being obtained for pure ZrN, while for Ti1−yTayN films a minimum was observed at y∼0.3. The evolution of the different film properties is discussed based on microstructrural investigations.

The combination of electrical conductivity, chemical and metallurgical stability, refractory character, having lattice constants that are close to those of III-nitrides makes transition metal nitrides promising candidates for electronics and device applications. We study the structure, stability, and the plasma energy of stoichiometric, transition metal nitrides of similar crystal quality as well as the widest variety of their ternaries ever reported. We establish the phase spaces of the plasma energy (6.9–10.5 eV) and the work function (3.7–5.1 eV) of these complex nitrides with their lattice constant (0.416–0.469 nm) and we investigate the limits of their applications.