Study of Deposition Temperature Effect on Defect Density in ZrN Thin Films by Positron Annihilation

Zirconium nitride (ZrN) thin films deposited on silicon substrates by PVD reactive sputtering at different substrate temperatures were studied by positron annihilation spectroscopy. The performance of such hard coatings is controlled by their microstructure in which open volume defects play a large role. The results show lower concentration of vacancies as the deposition temperature is increased, very short positron diffusion lengths in all samples indicate the existence of high density of grain boundaries which means small grain sizes. The optimum deposition temperature was observed to be between 300 °C and 400 °C. The study shows the importance of the positron spectroscopy as a motoring tool for the development of ZrN films.