NbN/MgO/NbN Josephson tunnel junctions fabricated on thin underlayers of MgO

Conference · Wed Mar 01 04:00:00 EST 1989 · IEEE Trans. Magn.; (United States)

OSTI ID:6087525

Kerber, G L; Cooper, J E; Morris, R S; Spargo, J W; Toth, A G

Underlayers of MgO as thin as 8.0 nm have been used in the fabrication of NbN/MgO/NbN Josephson tunnel junctions. NbN/MgO/NbN trilayers with and without MgO underlayers were deposited on thermally oxidized Si substrates at 100/sup 0/C using RF magnetron sputtering in a semi-UHV load lock vacuum system. Sputtering parameters were first optimized to produce NbN with T/sub c/ = 14.7 K on SiO/sub c//Si substrates, and then, thin MgO underlayers were used to enhance the T/sub c/ of the trilayers to 15.7 K. X-ray diffraction of NbN films indicates that thin MgO underlayers of 8.0 nm are capable of almost completely removing the NbN (111) diffraction peak found in lower T/sub c/ films and enhancing the NbN (200) peak. MgO underlayers were found to be oriented in the (100) direction when sputtered in an atmosphere of Ar and N/sub 2/ and randomly oriented when sputtered in an Ar alone. The authors present details for the preparation and analysis of NbN and MgO films as well as the fabrication and electrical performance of tunnel junctions with and without MgO underlayers.

• Research Organization: Hughes Aircraft Co., Carlsbad, CA (US)
• OSTI ID: 6087525
• Report Number(s): CONF-880812-
• Conference Information: Journal Name: IEEE Trans. Magn.; (United States) Journal Volume: 25:2
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE
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71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
DESIGN
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON TUBES
ELECTRONIC EQUIPMENT
EQUIPMENT
FABRICATION
FILMS
JOSEPHSON JUNCTIONS
JUNCTIONS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MAGNETRONS
MICROWAVE EQUIPMENT
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NIOBIUM COMPOUNDS
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NITRIDES
NITROGEN COMPOUNDS
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OXIDES
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PERFORMANCE
PHYSICAL PROPERTIES
PNICTIDES
REFRACTORY METAL COMPOUNDS
SPUTTERING
SUPERCONDUCTING FILMS
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
TUNNELING
VACUUM SYSTEMS