FORMATION OF EPITAXIAL AND TEXTURED PLATINUM FILMS ON CERAMICS-(100) MGO SINGLE-CRYSTALS BY PULSED-LASER DEPOSITION

We have investigated the formation of textured and epitaxial metallic films on (100) MgO single crystals substrates (lattice constant a=4.21 angstrom) as a function of deposition temperature during pulsed laser ablation. Platinum (a=3.92 angstrom) films on MgO with lattice misfit of 7.4% were found to grow epitaxially in the temperature range 500-700-degrees-C. Three-dimensional x-ray diffraction results (theta, phi, and chi scans) show [100] epitaxy with the alignment of all three cube axes. Rutherford backscattering and channeling measurements on a film deposited at 700-degrees-C showed a minimum yield of 2.2%, which is very close to the defect-free single crystal value. In the temperature range 200-500-degrees-C both [100] and [111] textures were observed. The [111] oriented (normal to the surface) films were random in the plane of the substrate, whereas [100] crystallites were epitaxial. Below 200-degrees-C, only [111] crystallites were observed. The [111] texture of platinum films is also observed when grown on amorphous substrates such as SiO2. The experimental results are normalized with theoretical simulations addressing the minimization of film energy.