Design and optimization of dc SQUIDs fabricated using a simplified four-level process

Conference · Thu Feb 28 23:00:00 EST 1991 · IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (United States)

OSTI ID:6092985

Cantor, R; Ryhanen, T; Drung, D; Koch, H ^[1]; Seppa, H ^[2]

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1. Physikalisch-Technische Bundesanstalt, Institut Berlin, Abbestr. 10-12, D-1000 Berlin 10 (DE)
2. VTT Metrology Research Inst., Technical Research Center of Finland, Otakaari 7B, SF-02150 Espoo (FI)

This paper describes an optimization procedure which we have used to design two types of ultralow noise dc Superconducting Quantum Interference Devices (SQUIDs) with integrated flux coupling circuits, a magnetometer and a gradiometer. Essential to this design approach is the reduction of the parasitic capacitance, the choice of a layout which moves the input coil resonances well away from the desired operating frequency of the SQUID, and the proper damping of these resonances. We show that both the microwave and LC resonances can be damped in a nearly noise free manner by placing an RC shunt in parallel with the input coil. This leads to smooth voltage-flux modulation characteristics and significantly improved noise performance. A simple, four-level Nb/Si{sub x}N{sub y}/Nb Josephson junction technology is described for device fabrication.

• OSTI ID: 6092985
• Report Number(s): CONF-900944--
• Journal Information: IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (United States), Journal Name: IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (United States) Vol. 27:2; ISSN IEMGA; ISSN 0018-9464
• Country of Publication: United States
• Language: English

Related Subjects

665411 -- Basic Superconductivity Studies-- (1992-)
665412* -- Superconducting Devices-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COUPLING
DESIGN
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
EQUIPMENT
FABRICATION
FLUXMETERS
JOSEPHSON JUNCTIONS
JUNCTIONS
MAGNETIC FLUX
MAGNETOMETERS
MEASURING INSTRUMENTS
MICROWAVE EQUIPMENT
NIOBIUM COMPOUNDS
NIOBIUM NITRIDES
NITRIDES
NITROGEN COMPOUNDS
NOISE
OPTIMIZATION
PHYSICAL PROPERTIES
PNICTIDES
REFRACTORY METAL COMPOUNDS
SILICON COMPOUNDS
SILICON NITRIDES
SQUID DEVICES
SUPERCONDUCTING DEVICES
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTIVITY
TEMPERATURE NOISE
TRANSITION ELEMENT COMPOUNDS