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Fabricating Contact Metallurgy to High-Temperature Superconductors

IP.com Disclosure Number: IPCOM000037442D
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Chang, CA: AUTHOR

Abstract

High temperature superconductors can be fabricated in thin film form, and require low-resistance contacts for device applications. Such contacts can be made by applying the contact layer (such as Ag) prior to annealing the superconductor film.

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Fabricating Contact Metallurgy to High-Temperature Superconductors

High temperature superconductors can be fabricated in thin film form, and require low-resistance contacts for device applications. Such contacts can be made by applying the contact layer (such as Ag) prior to annealing the superconductor film.

Thin film superconductors (YBA2 Cu3 07-x) were fabricated by depositing Cu/BaO/YO layer structures onto different substrates. Using an MgO substrate, and an 1:2:3 ratio among the layer thicknesses of YO, BaO and Cu, annealing in an oxygen ambient at 900oC forms thin film superconductors with a Tc exceeding 77K. A second sample of Ag/Cu/BaO/YO, with a layer thickness of 1000Ao for Ag, was deposited sequentially without breaking the vacuum. The Cu, BaO, and YO layers in this structure are identical to those of the structure without the Ag layer. Annealing of the Ag/Cu/BaO/YO structure under the same conditions allows the formation of YBaCuO superconductors with a Tc similar to that without the Ag layer. Films with the Ag layer show unreacted metallic Ag after the annealing, with a lower electrical resistance than the corresponding ones without the Ag layer. With a proper choice of the starting Ag layer thickness, this technique allows the fabrication of a contact metallurgy to the superconducting oxide with a very low contact resistance. It also avoids completely the interface adhesion problem which exists between the contact metal and an oxide surface. Furthe...