Production method for composite oxide thin film and device therefor and composite oxide film produced thereby

A method of making a thin film of a Cu group high temperature superconductor wherein the superconductor has a basic unit cell comprised of a charge supply block and a superconducting block, comprising:

• heating, in a vacuum atmosphere, an oriented crystalline substrate to a surface diffusion temperature;
• forming, in said vacuum atmosphere, a buffer layer on said heated substrate by sputtering from a target for the charge supply block in which Cu atoms are partially substituted with atoms capable of bringing about a chemical self-assembling effect;
• and then
• introducing an oxidizing gas under a selected pressure into said vacuum atmosphere;
• a) forming epitaxially a first block constituting said superconducting block by sputtering from a target for superconducting block until said first block being formed has its thickness determined for said superconducting block in said basic unit cell;
• b) forming epitaxially a second block constituting said charge supply block on said first block by sputtering from the target for the charge supply block until said second block being formed has its thickness determined for said charge supply block in said basic unit cell;
• repeating steps a) and b) to make a thin film of the Cu high temperature superconductor having a selected thickness on said buffer layer;
• and then
• c) forming an insulating layer having a selected film thickness on said formed thin film of Cu high temperature superconductor by sputtering from a third target made of an insulating material;
• and then
• repeating steps a) and b) or steps b) and a) to make a thin film of the Cu high temperature superconductor having a selected thickness;
• wherein said buffer layer satisfies lattice matching condition for the orientated crystalline substrate and the first block.