2-BEAM LASER DEPOSITION PROCESS FOR Y1BA2CU3O7-X FILMS ON SILICON

Two synchronized Nd-YAG lasers are used for ablation of solid targets in the two-beam laser deposition technique. Surface morphology and structure of YBaCuO films are successfully improved by application of this method. Droplets on the film surface are avoided, which is very important for the growth of thin buffer layers. ZrO2 buffer layers have been prepared on Si(100) substrates by this technique within two regimes, ablation of metallic zirconium in oxygen atmosphere as well as under vacuum conditions and afterwards in oxygen atmosphere as one-step and two-step process, respectively. Pretreatment of the silicon surface before the deposition process is not necessary. c-axis oriented and textured superconducting Y1Ba2Cu3O7-x (YBCO) films as determined by theta-20 X-ray diffraction and rocking curves are grown on the ZrO2 buffer layers. A zero resistance superconducting transition temperature of 88.5 K is measured. The interdiffusion between silicon and the YBCO material is strongly suppressed by a two-step in-situ deposition technique of the ZrO2 buffer layer of only 20 nm.