Fabrication of submicrometer features in Y-Ba-Cu-O superconducting thin films

The authors explored some of the processes required to fabricate superconducting devices in Y-Ba-Cu-O thin films. Photolithography was used to define superconducting wires with dimensions from several micrometers to less than one micrometer in films grown both by laser and electron-beam deposition. Patterns were transferred with a variety of techniques including lift-off, chemical etching, and argon ion milling. Low-resistance contacts were reliably made by in situ Ar ion beam presputter and Au or Ag deposition. Submicrometer wires produced with these processes behaved as scaled-down bulk superconducting films; wire properties were determined largely by initial film morphology and wire geometry. No naturally occurring weak link behavior was observed in wires down to 0.5 μm in width. The fabrication process and the electrical behavior of the resulting wires are discussed.