Browse Prior Art Database

Pb Alloy Josephson Junctions Delineated by Etching

IP.com Disclosure Number: IPCOM000087188D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Broom, RF: AUTHOR [+2]

Abstract

Problems in manufacturing Josephson devices related to environmental changes during processing can be avoided by taking advantage of the solubility of Pb and certain Pb alloys in water as follows:

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Pb Alloy Josephson Junctions Delineated by Etching

Problems in manufacturing Josephson devices related to environmental changes during processing can be avoided by taking advantage of the solubility of Pb and certain Pb alloys in water as follows:

The M2 pattern is deposited in the usual way and the film when oxidized to form the tunnel barrier. A thin film of pure Pb of about 1000-2000 Angstroms is then deposited to form the M3A counter electrode. After stripping the photoresist, the M3A film is removed from all parts of the M2 layer where junctions are not required. This is done by defining the junction areas with a coating of resist and washing off the exposed region of the M3A layer.

The junction edges are later protected with an insulating film, and superconducting contacts are made to the M3A layer by a Pb + Au M3B film.

Pure Pb is recommended for the M3A layer as opposed to Pb + 2.5 wt % Au to avoid any problems with residual platelets after washing off the film.

1