Fabrication of 123-type high-Tc superconducting thin films on BaZrO3-buffered MgO substrates

We have developed a stable preparation process for high-quality thin films of YBa2Cu3Oy (123)-type high-Tc superconductors (HTS) for the ground plane of single-flux-quantum (SFQ) devices. The films were deposited on MgO (100) substrates by an off-axis DC magnetron sputtering method. During deposition, the substrates were directly heated by thermal radiation from a heater. No adhesive paste was used for fixing the substrate. Possibility of chip contamination due to the paste could be completely eliminated. The insertion of a BaZrO3(BZO)-buffer layer was effective to obtain flat epitaxial 123 films with complete c -axis orientation. The flat ground plane could play a role as a suitable foundation for multilayer films of SFQ devices. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)