| 摘要 |
PURPOSE:To enable to manufacture the titled element with good reproducibility by the increase of the ratio of sub gap resistance to tunnel resistance by a method wherein the mixture ratio of vapor to oxygen in a mixed gas is controlled at a constant value by the use of a mixed gas plasma turned plasmatic containing oxygen and vapor in the oxidizing treatment with high frequency plasma. CONSTITUTION:While a plasma reaction chamber 11 is exhausted by an exhaust means 18, O2 and either one or both of vapor and H2 are introduced by a gas introducing means 12, and these introduced gasses are excited by a high frequency excitation means 23. The surface of the unmasked region of a superconductor layer 2 on a substrate 6 is oxidized with the mixed gas plasma, resulting in the formation of a tunnel barrier film 3 on the surface of the layer 2. Thereat, the mixture ratio of the vapor to the O2 in the chamber 11 is measured by a means 25 for measuring the mixture ratio, which is then controlled at 0.5vol. % or more by the control of the gas introducing means 12 by a control means 30. After the exhaust of the reaction chamber 11 is finished, a conductor substrate 7 is taken out of the chamber 11, and accordingly the second superconductor layer 4 is formed on the barrier film 3, thus obtaining the titled element.
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