Ga lithography in sputtered niobium for superconductive micro and nanowires

Journal Article · Mon Aug 18 00:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4893446· OSTI ID:22310898

Henry, M. David; Wolfley, Steve; Monson, Todd; Lewis, Rupert ^[1]

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1. Sandia National Labs, MESA Facility, P.O. Box 5800, Albuquerque, New Mexico 87185-1084 (United States)

This work demonstrates the use of focused ion beam (FIB) implanted Ga as a lithographic mask for plasma etching of Nb films. Using a highly collimated Ga beam of a FIB, Nb is implanted 12 nm deep with a 14 nm thick Ga layer providing etch selectivity better than 15:1 with fluorine based etch chemistry. Implanted square test patterns, both 10 μm by 10 μm and 100 μm by 100 μm, demonstrate that doses above than 7.5 × 10{sup 15 }cm{sup −2} at 30 kV provide adequate mask protection for a 205 nm thick, sputtered Nb film. The resolution of this dry lithographic technique is demonstrated by fabrication of nanowires 75 nm wide by 10 μm long connected to 50 μm wide contact pads. The residual resistance ratio of patterned Nb films was 3. The superconducting transition temperature (T{sub c}) = 7.7 K was measured using a magnetic properties measurement system. This nanoscale, dry lithographic technique was extended to sputtered TiN and Ta here and could be used on other fluorine etched superconductors such as NbN, NbSi, and NbTi.

• OSTI ID: 22310898
• Journal Information: Applied Physics Letters, Vol. 105, Issue 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
FILMS
GALLIUM
ION BEAMS
LAYERS
MAGNETIC PROPERTIES
MICROSTRUCTURE
NANOSTRUCTURES
NANOWIRES
NIOBIUM
NIOBIUM COMPOUNDS
NIOBIUM NITRIDES
NITROGEN COMPOUNDS
QUANTUM WIRES
SILICON COMPOUNDS
SPUTTERING
SUPERCONDUCTIVITY
TEMPERATURE RANGE 0000-0013 K
TITANIUM COMPOUNDS
TITANIUM NITRIDES
TRANSITION TEMPERATURE