Applications of ZrO2 - CeO2 - La2O3 Films in Multilayered Oxide Heterostructures

The pulsed laser deposition of cerium-based oxides Zr1-xCexO2 and Ce1-xLaxO2-x/2 has been studied in order to prepare buffer layers tailored to the epitaxial growth on Si, LaAlO3, SrTiO3 and MgO. It has been shown that these oxides with a wide variation of lattice constant (0.515-0.552 nm) could be obtained as epitaxial films with low roughness. The target composition, either metallic alloy or sintered oxide ceramic, can strongly influence the crystallinity and surface roughness of the grown films even if the chemical composition of films is the same. High-quality buffers were also grown with a 45o rotation of the in-plane axes with respect to those of the substrates LaAlO3 and SrTiO3. Such a type of growth was used also to obtain a heteroepitaxy for the oxide films with lattice constant ~ 0.36 0.39 nm. The quality of Zr1-xCexO2 buffer layers grown on (001) silicon is beginning to approach the surface quality of YSZ substrates and the best degree of film crystallinity with the minimum of surface microrelief was obtained using Zr-12%Ce alloy target.