Superconducting YBa2Cu3O7-δ thin film and thin film device fabrication on silicon substrates

The authors report the deposition of textured yttria-stabilized ZrO2 films (YSZ) and superconducting YBa2Cu3O7-δ films, using on-axis reactive (10% oxygen) rf diode sputtering, on both in-situ heated and unheated silicon substrates. They have fabricated high-Tc c-axis YBCO films (Tczero = 87 K) on heated substrates (500--600 degrees C) requiring low temperature (500--600 degrees C) post-deposition oxygen anneals and randomly oriented films (Tczero = 84 k) on unheated substrates requiring high temperature post-deposition oxygen annealing (850 degrees C) to become superconducting. The temperature dependence of the critical current density (Jc) of these films was related to their crystal orientation. They have measured the effect of the sputtering gas pressure, the target-to-substrate spacing, and the substrate temperature on the YBCO film composition. Simple YBCO/Au/Si Schottky diodes and Au/YSZ/YBCO/YSZ/Si multilayer structure have been fabricated