| 摘要 |
PROBLEM TO BE SOLVED: To enable a Josephson junction device to be lessened in junction capacitance and shortened in switching delay by a method wherein a multilayered film, composed of one of a film of material selected from among silicon oxide, silicon nitride, and boron nitride and an aluminum film, is made to serve as a barrier layer. SOLUTION: Silicon dioxide is deposited on a silicon substrate by sputtering carried out in an argon atmosphere through a high-frequency magnetron for the formation of a base insulating film 2, and niobium and aluminum are deposited thereon by direct-current magnetron sputtering carried out in an argon atmosphere. High-frequency magnetron sputtering is carried out in an argon atmosphere to deposit silicon without breaking a vacuum. Aluminum is partly oxidized at a spot where a silicon layer is thin, by the surface of a niobium layer is completely covered with aluminum. A tunnel current becomes smaller in an aluminum oxide than in a silicon dioxide. Silicon dioxide is deposited on the base insulating film 2, a main tunnel barrier layer 5, and an upper electrode 6 and then is subjected to etching with a photoresist film as a mask into an interlayer insulating film 7.
|
