| 摘要 |
PURPOSE:To increase the Josephson current of a semiconductor coupled superconducting circuit device and to decrease the dispersion of the Josephson current in a chip, by making it possible to form first and second superconducting electrodes on a semiconductor in close proximity by a distance of about the coherence length of electrons. CONSTITUTION:A superconductor, which is provided in contact with the upper part of a substrate 1, is patterned, and a superconducting electrode (I) 2 is formed. A plasma oxide film 3 covering the superconducting electrode 2 is formed to a thickness, which can block a tunnel current, by a plasma oxidation method. Thereafter, a superconducting electrode (II) 4, which has a part contacted with the semiconductor substrate 1 and has a part that is overlapped with the plasma oxide film 3, is formed. Thus, the superconducting electrodes 2 and 4 are arranged on the semiconductor substrate 1, so that the electrodes are separated by the thickness of the plasma oxide film 3. The thickness of the plasma oxide film can be controlled at the accuracy of several tens of nm. Therefore, the distance between the superconducting electrodes 2 and 4 can be made shorter than the distance, which can be achieved by a minute machining technology using conventional lithography method and etching method, and the uniformity is improved. |
