| 摘要 |
PURPOSE:To prevent the presence of impurities and remaining dust in a junction oxide film, to improve the reproducibility of characteristics, and to improve uniformity in a wafer and the reproducibility among the wafers, by performing the steps, by which a lower electrode, the junction oxide film, and an upper electrode are sequentially formed on a substrate, on which a lower electrode pattern is formed, in the same vacuum device. CONSTITUTION:A lower electrode pattern is formed on a substrate 1. A super- conducting metal, which is to become a lower electrode 3, is evaporated in a vacuum device. Then an O2 gas is introduced. Plasma is yielded in the vacuum device. The entire surface of the lower electrode is oxidized, and a junction oxide film 4 is formed. At this time point, the introduction of O2 is stopped, and a high vacuum state is restored. Thereafter, an upper electrode made of Pb-Au, Pb-Bi, Pb-In, or the like is evaporated. Then, patterning is performed so that a part where Josephson junction is formed is covered by photoresist. A part, which is not coated by the photoresist, is oxidized by O2 plasma, and the element is separated. After a thick junction separating oxide film 6 is formed, the photoresist is lifted off.
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