Superconducting circuit elements with metallic substrate and method for manufacturing the same

US5266558A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Frank Lichtenberg · Adliswil, CH
• Jochen Mannhart · Eppelheim, DE
• Darrell G. Schlom · Thalwil, CH

Key dates

• Filing date: Feb 27, 1992
• Grant date: Nov 30, 1993
• Expiry date: Feb 27, 2012

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S505/729

Abstract

These superconducting circuit elements, namely SNS heterostructures, such as, e.g. Josephson junctions and field-effect transistors, have a sandwich structure consisting of at least one layer of high-T.sub.c superconductor material arranged adjacent to a metallic substrate, possibly with an insulating layer in between, the substrate, the superconductor and--if present--the insulator all consisting of materials having at least approximately matching molecular structures and lattice constants. Electrical contacts, such as source, drain and gate electrodes are attached to the superconductor layer and to the substrate, respectively. The electrically conductive substrate consists of a metallic oxide such as strontium ruthenate Sr.sub.2 RuO.sub.4, whereas the superconductor layer is of the copper oxide type and may be YBa.sub.2 Cu.sub.3 O.sub.7-.delta., for example. The insulator layer (10) may consist of SrTiO.sub.3. The manufacture of these devices starts with the preparation of the substrate material from a 2:1,1 molar ratio of SrCO.sub.3 to RuO.sub.2 and involves a floating zone melting process yielding single crystals of the strontium ruthenate Sr.sub.2 RuO.sub.4 material onto whose…