Superconducting W-C nanopillars fabricated by Ga+ focused ion beam induced deposition

Elucidating the role of disorder introduced by nitrogen in the superconducting properties of tungsten thin films

“…When nitrogen impurities stabilize -phase, the films display T c up to 4.7 K 5 . The latter agrees with reports for amorphous structures obtained by focused ion beam (FIB) assisted deposition [13][14][15][16] , suggesting that the disorder at the nanoscale plays a role in the superconducting properties of W nanostructures. Indeed, nanowires with T c  4.8 K were obtained by FIB using tungsten hexacarbonyl and a gallium beam where the impurities are mainly C, Ga and O [13][14][15] .…”

“…A particular highlight of these samples is that they display T c comparable to nanowires obtained by FIB. 13–16 Moreover, the superconducting properties are similar to those observed in amorphous superconductors such as MoSi 32 and WSi. 33 The latter are materials typically used for designing SNSPD, characterized by fast response time.…”

“…6). A particular highlight of these samples is that they display T c comparable to nanowires obtained by FIB [13][14][15][16] . Moreover, the superconducting properties are similar to those observed in amorphous superconductors such as MoSi 32 and WSi 33 .…”

Gas-Phase Synthesis of Iron Silicide Nanostructures Using a Single-Source Precursor: Comparing Direct-Write Processing and Thermal Conversion

“…It should be noted that the lowest resistivity values for other FIBID deposits derived by Ga + ions based on Pt (∼800 μΩ·cm), Pd (∼1000 μΩ·cm), Co 2 Si (∼330 μΩ·cm), and W (∼200 μΩ·cm) , typically are fairly high when compared to those of pure metals. Exceptions are the higher-purity Cu (∼50 μΩ·cm) and Co-based (∼20 μΩ·cm) FIBID material, but significant differences have been observed depending on compositional changes and postgrowth processing.…”

“…General introductions to the subject, including the physics of beam–substrate interactions ,, and suitable precursors for FEBID/FIBID, − are available. The main differences between the exclusively additive FEBID and the more complex FIBID are the incorporation of ions into the growing material, implantation into the substrate, and damage to the substrate material either by amorphization or localized sputtering of the substrate/deposit due to the momentum transfer of the ions. , For example, Ga + ion sources inherently result in the incorporation of Ga into the growing material and thus in a material composition that is dependent on the growth rate. − Inadvertent incorporation of the ion source material into the deposit can be prevented by using alternatives such as gas field ion source processing for FIBID. , While similar effects occur for different ions, the specific contributions to sputtering, energy transfer, and fragmentation efficiency of precursor moieties is determined by ion mass, size, and energy. , …”