Thermal stability of magnetron sputtered Zr–Si–N films

The article reports on thermal stability of the structure and mechanical properties of Zr–Si–N films with a high (≥ 25 at.%) Si content deposited from a ceramic ZrSi2 target by reactive magnetron sputtering. The annealed films were characterized using X-ray diffraction, microhardness and macrostress measurements, and differential scanning calorimetry. Special attention was devoted to the influence of the annealing temperature (up to 1600 °C), annealing environment and presence of the substrate. It was found that the phase composition of the films strongly influences its thermal stability. Furthermore, (i) microhardness of the Zr–Si–N films sputtered under conditions used in our experiments is determined by their structure and not by the macrostress, (ii) crystallization of the X-ray amorphous films strongly depends on its phase composition, the ambient atmosphere and the incorporation of the substrate elements into the film due to interdiffusion during annealing, and (iii) X-ray amorphous Zr–Si–N films containing a high (≥ 50 vol.%) content of the Si3N4 phase exhibit the highest thermal stability considerably exceeding 1000 °C.