TUNNEL JUNCTION DEVICE COMPOSED OF COMPOUND OXIDE SUPERCONDUCTOR MATERIAL AND METHOD FOR FABRICATING THE SAME

摘要

A tunnel junction device includes a pair of superconduction layers formed of a compound oxide superconductor material and a non-superconduction layer formed between the pair of superconduction layers. The non-superconductive material layer is formed of a compound oxide superconductor material which is substantially the same as that of the first and second superconduction layers but which is doped with a dopant of an amount sufficient for the compound oxide superconductor material to lose the superconduction property. The first superconduction layer, the non-superconductive material layer and the second superconduction layer have a continuous crystal lattice as a whole. The above mentioned tunnel junction structure is formed by continuously depositing the compound oxide superconductor material on a substrate without interrupt of deposition from a beginning of the deposition of the first superconduction layer until a termination of deposition of the second superconduction layers, and adding a dopant concurrently with deposition of the compound oxide superconductor material only at the time of forming the non-superconduction layer, so that the first superconduction layer, the non-superconduction layer and the second superconduction layer are continuously formed in the named order without interrupt of deposition of the compound oxide superconductor material.