Y2O3 stabilised ZrO2 (YSZ) layers were deposited on (11 (2) over bar0) Al2O3 by sol-gel dip-coating, A low temperature heat treatment produces a poly crystalline film. Further heating at 1500 degreesC yields an epitaxial layer by grain growth of the islands with the lowest interfacial energy. We used a home-made high resolution diffractometer to record reciprocal space maps of the YSZ layer. The simulation of the diffraction profiles with a kinematical scattering model enables us to extract the strain profile within the layer, the average thickness and the vertical island size distribution, (C) 2002 Elsevier Science B.V. All rights reserved.