Influence of Annealing Temperature on the Microstructure and Hardness of TiN Coatings Deposited by High-Power Impulse Magnetron Sputtering

Titanium nitride (TiN) coatings were deposited on a silicon substrate using reactive high power impulsed magnetron sputtering (HiPIMS), without additional heating. The TiN films were annealed at different temperatures ranging from 200 to 600 °C, and the effect of heat treatment on the microstructure, morphology and mechanical properties of TiN was investigated using x-ray diffraction, Raman spectroscopy, atomic force microscopy and nanoindentation. The results are compared to the properties of conventional TiN coatings, typically deposited by DC magnetron sputtering or arc evaporation at around 400 °C. It is found that the hardness of the HiPIMS films increases from 16.4 to 21.8 GPa as the annealing temperature increases to 400 °C. For higher annealing temperatures, the hardness of coatings decreases, which is attributed to the oxidation of TiN.