Improvement of critical current uniformity in lead-alloy Josephson junctions

Journal Article · Sun Sep 15 04:00:00 EDT 1985 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.335946· OSTI ID:5451468

Imamura, T; Hasuo, S; Yamaoka, T

A lead-alloy Josephson junction with excellent uniformity of critical currents is proposed. The junction, consisting of a thin Pb-In-Au base electrode and an epsilon-phase Pb-Bi counterelectrode, is made on a thick Nb electrode. SiO openings, which define the junction area, are formed not after but before deposition of the base electrode. Using this structure, junctions can be formed free from any wet process of photolithography from the base to counter electrodes. Current-voltage (I-V) characteristics of series-connected junctions are measured and uniformity of the critical currents is estimated. Despite I-V characteristics representing large subgap current and small gap voltage, good uniformity of the critical currents is observed. The maximum to minimum spread of critical currents is +- 4.1% for a 186-junction chain with a junction area of 5 ..mu..m square. A standard deviation of 1.5% is obtained, a value about one-third of that obtained for the conventional lead-alloy junctions.

• Research Organization: Fujitsu Ltd., 10-1 Morinosato-Wakamiya, Atsugi 243-01, Japan
• OSTI ID: 5451468
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 58:6; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALLOYS
BISMUTH ALLOYS
CHALCOGENIDES
CRITICAL CURRENT
CURRENTS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
ELECTRODES
ENERGY GAP
FABRICATION
INDIUM ALLOYS
JOSEPHSON JUNCTIONS
JUNCTIONS
LEAD ALLOYS
NIOBIUM ALLOYS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SILICON COMPOUNDS
SILICON OXIDES
SUPERCONDUCTING JUNCTIONS