YBa2Cu3Ox-microstructures on semiconductor substrates

Thin films of YBa₂Cu₃O_x were prepared by laser ablation with a KrF excimer laser on Si and GaAs. These films show degraded superconducting properties compared to films on SrTiO₃, which exhibit critical temperatures T_cO=89 K and critical current densities J_c(77 K) in the 10⁶-A/cm₂ range. Critical temperatures of 57 K and 30 K for films on Si and GaAs, respectively, could be achieved. YBa₂Cu₃O_x microbridges on SrTiO₃ were prepared with widths down to 10 μm by wet chemical etching or by laser ablation through metal masks. Patterning of films on bare Si, however, is complicated by microcracks in the film due to different lattice constants and thermal expansion coefficients of Si and YBa₂Cu₃O_x. These problems may be overcome by the use of buffer layers, whose influence on the film quality is also discussed