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Self-aligned Edge Superconducting Device Fabrication

IP.com Disclosure Number: IPCOM000061420D
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gallagher, WJ: AUTHOR [+2]

Abstract

High gain superconducting devices using the difference in sensitivity in a superconductor between current carried by pairs and that carried by quasiparticles are fabricated by forming a microbridge joining two superconductor members on a beveled edge of a layered stack of a superconductor between two insulators.

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Self-aligned Edge Superconducting Device Fabrication

High gain superconducting devices using the difference in sensitivity in a superconductor between current carried by pairs and that carried by quasiparticles are fabricated by forming a microbridge joining two superconductor members on a beveled edge of a layered stack of a superconductor between two insulators.

An improvement in processing such a structure is achieved by deposition at an angle R as shown in the figure that permits both the bridge and the superconductors to be simultaneously deposited.

The bridge structure is formed in a single step by appropriately adjusting the edge angle, R. A uniform flux of evaporant is deposited at normal incidence on the substrate surf To first order, the deposited edge film thickness, dR, is given by dR = d(p)cosR, where d(p) is the planar (bank) film thickness. At R = 40, 60, and 80 degrees, d(p)/dR = 1.3, 2 and 5.8, respectively. The ratio d(p)/dR should be greater than 2 to minimize heating of the banks. Processing necessary to control the step edge angle to Å5 degrees is maintained. Dry etching with a hollow cathode configuration yields etch angles that can be controlled between 90 degrees and 50 degrees and has the advantage of being largely independent of the etched materials. Variations in the edge film smoothness can be reduced by adjustments in substrate temperature during film deposition.

Disclosed anonymously.

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