JP2732513B

PURPOSE:To obtain a 3-pole type oxide superconducting element containing oxide superconductor/semiconductor junction by generating carrier in an insulator capable of exhibiting superconductivity when an oxide superconductor is bonded. CONSTITUTION:An Nb2O5 is mixed within a starting material, an SrTrO3 single crystal doped with Nb as an impurity is grown, the single crystal doped with the Nb is cut out in a wafer state, its surface is mirror-polished, further immersed in hot phosphoric acid to etch its surface, thereby removing contaminant on the surface, a crystal defect, a distortion, etc., and an insulator (semiconductor) 1 in which carrier is generated is formed. Then, an oxide superconductor Er-Ba-Cu-O film is formed by a high frequency magnetron sputtering method, coated with resist, and processed by using an electron beam lithography method, an Ar ion etching method, thereby forming a source superconducting electrode 2 and a drain superconducting electrode 3. Thereafter, a gate insulating film 4, and a gate electrode 5 are formed to obtain a superconducting 3-pole element.