Zr–Si–N films fabricated using hybrid cathodic arc and chemical vapour deposition: Structure vs. properties

ZrSiN coatings with a nanocomposite structure consisting of ZrN crystallites connected by a thin layer of amorphous Si3N4 at the grain boundaries have been deposited on Si wafer substrates using a new hybrid PVD–CVD process. The microstructure and mechanical properties of coatings of varying Si content were compared. It was found that the addition of Si from a liquid precursor of tetramethylsilane (TMS) to ZrN results in an increase in hardness up to a Si concentration of ∼3 at.% but the hardness drops with further additions of Si. The grain size initially decreases dramatically to ∼10 nm with the addition of Si at 3 at.%, becoming more equiaxed. It then continues to decrease slowly as the Si content is increased. XPS spectra revealed the presence of phases other than ZrN and Si3N4, including ZrO, ZrC and elemental Si, however these phases are not observed in selected area diffraction patterns obtained in the transmission electron microscope.