Structural changes in Zr–Si–N films vs. their silicon content

Zr–Si–N films are deposited on silicon and steel substrates by DC magnetron sputtering of a Zr–Si composite target in Ar–N2 reactive mixture, with different Si contents. At very low silicon content, no Si–N bond is observed and Si atoms may be inserted in the lattice of ZrN, as confirmed by the strong increase in the compressive stresses. For intermediate Si contents, nanocomposite films are synthesised: [100] oriented ZrN grains are embedded in an amorphous SiNx phase. For a silicon content higher than 6 at.%, amorphous films are deposited. The variation of the films hardness vs. the silicon concentration is discussed as a function of the films structure and compressive stress level. Finally, the relationship between the hardness and Youngʹs modulus values is also presented.