Room temperature deposition of superconducting NbN for superconductor--insulator--superconductor junctions

Journal Article · Thu May 01 04:00:00 EDT 1986 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.573873· OSTI ID:5755171

Thakoor, S; LeDuc, H G; Thakoor, A P; Lambe, J; Khanna, S K

Reactive dc magnetron sputtering is used to deposit hard, refractory, superconducting thin films of niobium nitride on amorphous (glass) as well as crystalline (sapphire) substrates held at room temperature. Stoichiometric NbN films so obtained possess the desired B1 crystal structure with a distinct (111) texture, and exhibit high (approx.16 K) superconducting transition temperature. Room temperature deposition of the high T/sub c/ films is achieved primarily by optimizing the reactant fluxes of niobium and nitrogen reaching the substrate, through a systematic study of the nitrogen consumption versus injection characteristics which are found to be an absolute indicator of the quality of NbN formed. Superconductor--insulator--superconductor (SIS) junctions are fabricated by using high T/sub c/ NbN as the base electrode, a thin layer of native oxide grown in oxygen plasma or in room air as the insulator, and vacuum deposited Pb as the counterelectrode. The current versus voltage (I--V) characteristics of the junctions exhibit high (approx.110) nonlinearity parameter and the superconducting gap parameter for NbN, ..delta..approx.2.8 meV. The transition temperature, superconducting gap parameter, and nonlinearity parameter of the junctions are identical for the films deposited at room temperature with predominant (111) texture as well as the films deposited at elevated temperatures possessing (200) texture.

• Research Organization: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109
• OSTI ID: 5755171
• Journal Information: J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 4:3; ISSN JVTAD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
420201 -- Engineering-- Cryogenic Equipment & Devices
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
COATINGS
CORUNDUM
CRYSTAL STRUCTURE
DATA
DEPOSITION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ENERGY GAP
EXPERIMENTAL DATA
FABRICATION
FILMS
GLASS
INFORMATION
JUNCTIONS
MINERALS
NIOBIUM COMPOUNDS
NIOBIUM NITRIDES
NITRIDES
NITROGEN COMPOUNDS
NUMERICAL DATA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
REFRACTORY METAL COMPOUNDS
SAPPHIRE
SPUTTERING
SUPERCONDUCTING JUNCTIONS
SURFACE COATING
TEXTURE
THERMODYNAMIC PROPERTIES
THIN FILMS
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE