Influence of ultra-thin YSZ layer on heteroepitaxial CeO2/YSZ/Si(001) films analyzed by X-ray reciprocal space map

The heteroepitaxial CeO2(001)/YSZ(001)/Si(001) films with various YSZ thicknesses, from 0.5 to 36.0nm, were prepared by pulsed laser deposition (PLD). The film structure was characterized mainly by reciprocal space mapping performed on a high-resolution X-ray diffraction. In the case of 0.5 nm thick YSZ, the out-of-plane and in-plane lattice constants (a(n),a(p)) of CeO2 are much closer to Si, almost without tetragonal distortion. As the YSZ thickness increases above 0.5 nm, the CeO2 lattice is a tetragonal distortion with larger a(p) and smaller a(n). Besides, the CeO2 layer with 0.5 nm thick YSZ shows a wider dispersion of smaller mosaic domains, larger crystallographic tilt, and less strain condition than other YSZ thickness. (C) 2000 Published by Elsevier Science B.V. All rights reserved.