Conductus, Inc.

University of California

Stephen M Garrison

Nathan Newman

Kookrin Char

Gregory G Zaharchuk

Richard E Russo

Randy Wayne Simon

Paul H Berdahl

Ronald P Reade

A method for producing multilayer structures comprised of materials with incompatible processing parameters is disclosed. A bonding layer of arbitrary dielectric constant is applied to each of two substructures. Each substructure is composed of a substrate and at least one epitaxial crystalline layer. Examples of particular bonding materials used are polyimide, fluorocarbon polymers, other organic materials, and glass. The bonding material may be applied like photoresist, or sputtered, or applied in any appropriate manner consistent with the processing constraints of the crystalline materials. Structures formable in this way include superconductor-amorphous dielectric-superconductor and ferroelectric-insulator-semiconductor trilayers, as well as microwave resonators and multichip modules.

Method of bonding multilayer structures of crystalline materials

A process for depositing a biaxially aligned intermediate layer over a non-single crystal substrate is disclosed which permits the subsequent deposition thereon of a biaxially oriented superconducting film. The process comprises depositing on a substrate by laser ablation a material capable of being biaxially oriented and also capable of inhibiting the migration of substrate materials through the intermediate layer into such a superconducting film, while simultaneously bombarding the substrate with an ion beam. In a preferred embodiment, the deposition is carried out in the same chamber used to subsequently deposit a superconducting film over the intermediate layer. In a further aspect of the invention, the deposition of the superconducting layer over the biaxially oriented intermediate layer is also carried out by laser ablation with optional additional bombardment of the coated substrate with an ion beam during the deposition of the superconducting film.

Process for ion-assisted laser deposition of biaxially textured layer on

A novel method of producing weak-link grain boundary Josephson junctions in high temperature superconducting thin films is disclosed. These junctions are reliably and reproducibly formed on uniform planar substrates (10) by the action of a seed layer (40) placed intermediate the substrate (10) and the superconductor film (20). The superconductor film (22) grown atop the seed (42) is misoriented from the rest of the film (24) by an angle between 5.degree. and 90.degree.. The grain boundary (30) so formed acts as a high quality weak-link junction for superconductor devices. The performance of these junctions can be improved by the addition of buffer layers (50, 60) between the substrate (10) and the superconductor film (20).

Method of forming grain boundary junctions in high temperature

Grain boundary, weak-link junctions are formed at a predermined location of a uniform, planar substrate by depositing superconducting film on two sections of the substrate. The film is grown as a bicrystal having two distinct areas of superconducting film whose crystal lattices are rotated with respect to each other, either in-plane or out-of-plane, by more than 5.degree. and less than 90.degree.. The grain boundary acts as a weak link junction. The film can be induced to grow as a bicrystal by depositing intermediate strata such as seed layers or buffer layers or by modifying the growth conditions during deposition.

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Palo Alto, CA, United States of America

Stephen M Garrison