Superconducting properties of in-plane W-C nanowires grown by He ⁺ focused ion beam induced deposition

Abstract

Focused ion beam induced deposition (FIBID) is a nanopatterning technique that uses a focused beam of charged ions to decompose a gaseous precursor. So far, the flexible patterning capabilities of FIBID have been widely exploited in the fabrication of superconducting nanostructures, using the W(CO)₆ precursor mostly in combination with a focused beam of Ga⁺ ions. Here, the fabrication and characterization of superconducting in-plane tungsten-carbon (W-C) nanostructures by He⁺ FIBID of the W(CO)₆ precursor is reported. A patterning resolution of 10 nm has been achieved, which is virtually unattainable for Ga⁺ FIBID. When the nanowires are patterned with widths of 20 nm and above, the deposited material is superconducting below 3.5-4 K. In addition, nanowires with widths of 60 and 90 nm have been found to sustain long-range controlled nonlocal superconducting vortex transfer along 3 μm. Overall, these findings strengthen the capabilities of He⁺ FIBID of W-C in the growth and patterning of in-plane superconducting nanodevices.