Browse Prior Art Database

Manufacturing Josephson Junctions in a Single Step

IP.com Disclosure Number: IPCOM000084710D
Original Publication Date: 1975-Dec-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Walter, W: AUTHOR

Abstract

Manufacturing a Josephson junction by producing the bottom electrode, the tunnel oxide and at least a fractional layer of the top electrode within a single step, is essential for avoiding contamination and obtaining high-quality junctions.

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Manufacturing Josephson Junctions in a Single Step

Manufacturing a Josephson junction by producing the bottom electrode, the tunnel oxide and at least a fractional layer of the top electrode within a single step, is essential for avoiding contamination and obtaining high-quality junctions.

On the surface of a substrate which is insulating or covered by an isolation layer, a metal layer, preferably of niobium is deposited over the entire surface. A tunnel layer is produced immediately thereafter, and a thin-metal layer deposited on top of the surface.

To obtain the appropriate shape or pattern of the bottom electrode, a mask is applied and all metal of the protective layer and the bottom electrode outside the mask is oxidized. For niobium this is preferably done by electrolytic oxidation in a bath. By absorption of oxygen, the resulting oxide layer will be thick in comparison to the sandwiched layers before oxidation as indicated in the second drawing.

The mask which may consist of photosensitive lacquer is now stripped off and the top electrode is deposited. This electrode is shaped into its final pattern by oxidation, which is done after application of a second mask in a similar way as described above. The Josephson junction, device may then be finished in any conventional manner which is suitable for its intended use.

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