Anodized niobium as barrier for Josephson tunnel junctions

Journal Article · Wed Jul 15 04:00:00 EDT 1987 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.339745· OSTI ID:6487741

Aponte, J; Rivera, E; Sa Neto, A; Octavio, M

We have fabricated Nb-NbO/sub x/-Pb Josephson tunnel junctions in which the barrier is formed by anodization of the niobium electrode. The anodized barrier is made thick (>100 A) to then be sputter etched to the desired thickness. The geometry of the niobium electrode is defined by a selective anodization process and the lead electrode is patterned by chemical etching. The I-V characteristics of 10/sup -6/-cm/sup 2/ rectangular junctions have been measured at 4 K. Our junctions exhibit large leakage current and low I/sub C/R/sub N/ product, making them less attractive for practical applications than junctions made by other techniques. However, the ease of fabrication and reasonable reproducibility of the electrical characteristics of our junctions make our method of fabrication quite useful when high quality of the barrier is not a stringent requirement. Noise measurements in our junctions and electron diffraction analysis of niobium-oxide films grown by anodization confirm the presence of a large number of defects in the barrier.

• Research Organization: Fundacion Instituto de Ingenieria, Apartado 40200, Caracas 1040-A, Venezuela; Instituto Venezolano de Investigaciones Cientificas, Apartado 21827, Caracas 1020-A, Venezuela
• OSTI ID: 6487741
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 62:2; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
ELEMENTS
ETCHING
FABRICATION
JOSEPHSON JUNCTIONS
JUNCTIONS
LEAKAGE CURRENT
METALS
NIOBIUM
NIOBIUM COMPOUNDS
NIOBIUM OXIDES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
SPUTTERING
SUPERCONDUCTING JUNCTIONS
SURFACE FINISHING
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS