| 摘要 |
PURPOSE:To form a minute Josephson element with high accuracy in size by forming a minute opening on an insulating film and removing the part of corresponding area to said minute opening while leaving the wide area with regard to the patterning of a photoresist. CONSTITUTION:A lower electrode forming superconductive layer 21 is formed on an Si substrate 11 and immediately it is covered with a protective film 22 for which MgO is preferable to be selected in this case. When an SiO2 film 23 is formed and patterned, an opening 24 regulating a lateral size of the Josephson element is formed. In order to expose the surface part of the Nb layer 21 at the bottom of the opening 24 on the insulating layer 23, the protective layer 22 is removed by using the remaining part of the insulating layer 23 as a mask. As a result, the surface of the Nb layer 21 is exposed at the bottom of opening 24 as a lower electrode surface 25 and at the same time, the protective layer of the part uncoated with the insulating film 23 is removed. On the whole surface, a tunnel barrier forming material layer 26 is formed and subsequently, for example, a Nb layer 29 is formed. Then, the part in contact with the tunnel barrier 27 in the opening 24 becomes an upper electrode 30 of Josephson element. |
