| 摘要 |
PURPOSE:To contrive the improvement of corrosion resistance without damaging the characteristic, by forming the electrode material of a Josephson tunnel junction element of a thin film laminated structure by adding Bi and Cr to Pb. CONSTITUTION:The lower electrode 2 of the Josephson tunnel junction element is provided on a substrate 1 by continuously depositing by evaporating Au to 4.5nm, Pb to 160nm and In to 35.5nm, and a tunnel barrier layer 4 is provided on an aperture part of an SiO2 deposited film 3, while the upper electrode 5 is formed by continuously depositing by evaporating Pb to 136nm, Bi to 128nm, Pb to 136nm and Cr to 30-100nm. The lower electrode is easily changed into an alloy at a room temperature or the temperature of approx. 80 deg.C, and the upper electrode is likewise diffused and changed into an alloy except for Cr. Besides, Cr is diffused to the lowermost part of the film, and accordingly the corrosion resistance is improved. On the other hand, the temperature of superconductive transition is decreased more or less by the Cr diffusion into Pb-Bi, however, there is no hindrance in using this junction element for a logic and memory circuit. |
