Characterisation of CVD grown diamond and its residual stress state

One of the most important quality factors in the judgement of thin diamond layers is the adhesion between the substrate and the layer which is limited by the residual stress state. The main reason for residual stress in coatings is the misfit in various properties of the layer and also the substrate, e.g. thermal expansion and crystal lattice type. The most common method of residual stress determination, based on X-ray diffraction, has to date found little application in the study of diamond films. In this paper, the method is applied to determine the residual stress in a CVD diamond film grown on a polycrystalline Al substrate. The results are interpreted with regard to the crystal structure and orientation of the layer, determined by X-ray diffraction and scanning electron microscopy. (C) 1999 Elsevier Science S.A. All rights reserved.