Microstructure of high-k dielectric LaLu03 films on (001) SrTi03 Substrates

The microstructure of dielectric LaLuO3 films grown on SrRuO3-buffered (001) SrTiO3 substrates is investigated by means of transmission electron microscopy. A multi-domain structure is observed at the film areas close to the interface between the LaLuO3 and SrRuO3 layers in both cross-section and plan-view samples. In these areas, the domains grow with either the 110 or the [001] crystallographic direction parallel to the normal of the film. With increasing film thickness, the [0011 domains are found togrowoverthe other types, resulting in a microstructure of [001]-orientated domains with 90 degrees in-plane rotation in the top part of the film. Lattice defects such as dislocations and lattice strain at the domain boundaries are studied and discussed in the light of the difference between the lattice parameters. (C) 2008 Elsevier B.V. All rights reserved