Microstructure evolution of ZrN films annealed in vacuum

Microstructure changes of ZrN films deposited onto Si substrates by unbalanced magnetron sputtering were investigated over temperatures of 200-1100 degrees C in vacuum. The microstructure and morphology of the films were investigated by means of X-ray diffraction and field-emission scanning electron microscopy. The residual stress was determined using a laser scanning curvature measurement method. Neither color change nor oxides could be discerned over the whole investigated temperature. Scarce round micro-blisters, due to the increase of residual compressive stress in the films, were found above 400 degrees C. The texture coefficient, lattice parameter, and average strain of the films varied with annealing temperature. The measured residual stresses reached a minimum, i.e., -7.0 GPa at 400 degrees C. Subsequently, the stress relaxed with temperature and became tensile at 1000 degrees C. Additionally, the Young's Modulus of the films could be obtained from the residual stress and average strain relation. The evaluated value was 380 +/- 70 GPa, which is comparable to those reported from the literature; nevertheless, this technique is nondestructive and much simpler. (c) 2005 Elsevier B.V. All rights reserved.