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.