| 摘要 |
PURPOSE:To alleviate the increase in capacity between a wiring layer and a first electrode and to make an insulating layer thin, by forming an Nb anode oxide film as an insulating layer, and forming an insulating film, whose permittivity is lower than that of the Nb anode film, on said film. CONSTITUTION:A tunnel barrier 3 and a second electrode 4 are formed in an island shape on a first electrode 2. Thereafter, an Nb anode oxide film 5 is grown to a thickness of, e.g., about 300Angstrom by an anode oxidation method. At this time, the anode oxide film 5 is formed on the upper part of the first electrode 2, the side surface part of the tunnel barrier 3 and the side surface part of the second electrode 4. Then an insulating film, e.g., an SiO layer 7, whose permittivity is lower than that of the anode oxide film 5, is deposited to a thickness of about 1,000Angstrom by resistance heating. Thereafter, a wiring layer 6 is formed. In this constitution, since the anode oxide film 5 is as thin as about 300Angstrom , the undercutting at the time of anode oxidation is small and its junction having a minute area can be found. The thickness of SiO layer 7 is about 1,000Angstrom and thin. Since the anode oxide film 5 is used together, the insulation property of the insulating layer formed by both the layer 7 and the film 5 is excellent. |
