| 摘要 |
PURPOSE:To contrive to be able to obtain a tunnel junction having uniform characteristics by a method wherein the tunnel junction is constituted of an Nb thin film having a uniform crystalline orientation, a metal thin film, an oxide film formed thereon and a superconducting thin film and the oxide film is used as the surface oxide layer of the metal thin film. CONSTITUTION:To make uniform the crystalline orientation of a lower electrode Nb film 2 is an essential condition for uniformizing the film thickness of an oxide film which is a tunnel barrier layer 4. There, when the lower electrode 2 consisting of Nb, the tunnel barrier layer 4 consisting of Al oxide or Mg oxide and an upper electrode film 5 consisting of Nb, which consist a tunnel junction, are continuously formed, the temperature of a substrate 1 at the time of formation of the film 2 is set at 300 deg.C or more or a film made using a base material having an interatomic interval to coincide with that of Nb is used as the Nb film 2 having a uniform crystalline orientation. As the tunnel barrier layer 4, a layer obtainable by a method, wherein an Al or Mg thin layer is formed on the Nb film 2 having a uniform crystalline orientation and the surface layer is oxidized, is used. Thereby, the tunnel characteristics can be uniformized.
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