Browse Prior Art Database

Multi-Layer Structures for High Temperature Superconducting Devices

IP.com Disclosure Number: IPCOM000119461D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 1 page(s) / 45K

Publishing Venue

IBM

Related People

Gallagher, WJ: AUTHOR [+3]

Abstract

A technique is described whereby a multi-layer structure provides a means of incorporating high temperature superconducting devices, such as tunnel junctions, field-effect transistors and Josephson devices. The structures are unique in that materials used are similar to that used in semiconductor heterostructure devices, but the range of possible material properties is wider with compositions near the metal-insulator transition.

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Multi-Layer Structures for High Temperature Superconducting Devices

      A technique is described whereby a multi-layer structure
provides a means of incorporating high temperature superconducting
devices, such as tunnel junctions, field-effect transistors and
Josephson devices.  The structures are unique in that materials used
are similar to that used in semiconductor heterostructure devices,
but the range of possible material properties is wider with
compositions near the metal-insulator transition.

      The concept described herein centers about materials in the
LaCuO, YBaCuO, TlBaCaCuO, and BiSrCaCuO families with compositions
near the metal-insulator transition.  Small variations in composition
have a large influence on properties without significant structural
changes.  This allows the fabrication of multi-layer structures which
are nearly composition matched and/or lattice matched.

      One application is to use a graded film from metallic (near
superconducting) through an insulator.  The near superconducting film
is easily induced into the superconductivity state by a change in
carrier concentration.  The insulator film will have little trapped
charge at the interface region.  Furthermore, it can be made with
ferroelectric properties further enhancing the possible change in
carrier concentration with applied gate voltage.

      The concept concentrates on layers of materials which are very
similar in makeup, differing in doping, defect co...