| 摘要 |
PURPOSE: To form an insulating film having the excellent crystallinity, reduce a leakage current and improve the tunnel junction characteristics by a method wherein an oxide insulating layer made of cubic crystal perovskite oxide containing Ba and 0 is formed on an oxide superconductor having a specific composition. CONSTITUTION: An oxide insulating film 3 made of BaCeO3 is formed on an oxide superconducting thin film 2 whose composition is Ba1-x Kx BiO3 (wherein (x) is 0.2<=x<=0.5). As the BaCeO3 thin film can be formed at a substrate temperature of 300 deg.C, a reaction at the BKBO interface hardly occurs when the film is formed. Further, as the lattice constant of BKBO is 4.28Åand the lattice constant of BaCeO3 is 4.397Å, the mismatching of the lattice constant is small. Therefore, the oxide insulating film 3 having the excellent crystallinity can be formed on the superconducting thin film 2 made of BKBO by epitaxial growth.
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