The origin of stresses in magnetron-sputtered thin films with zone T structures

In order to understand the origin of the residual stress state in thin films and its thickness dependence, the structure stress relation of magnetron-sputtered Cr and CrN layers with thicknesses ranging from 100 nm to 3 mu m was investigated in detail. Based on correlations between the layer-thickness-dependent grain size, texture and morphology and the magnitude of the intrinsic and thermal components of the residual stress, a model is proposed that explains the origin of internal stresses of thin polycrystalline films with zone T structures. The model was further extended for the CrN/Cr dual-layer system, where the CrN top layer is epitaxially aligned with the underlying highly (2 0 0)-oriented Cr interlayer. It is shown for the first time that both the intrinsic and thermal stress components are thickness-dependent, which is associated with the layer microstructure. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.