English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Understanding the origins of power loss in superconducting interconnects isessential for the energy efficiency and scalability of superconducting digitallogic. At microwave frequencies, power dissipates in both the dielectrics andsuperconducting wires, and these losses can be of comparable magnitude. A novelmethod to accurately disentangle such losses by exploiting their frequencydependence using a multi-mode transmission line resonator, supported by ageometric factor concept and a 3D superconductor finite element method (FEM)modeling, is described. Using the method we optimized a planarized fabricationprocess of reciprocal quantum logic (RQL) for the interconnect loss at 4.2 Kand GHz frequencies. The interconnects are composed of niobium ($\rm Nb$)insulated by silicon dioxide made with a tetraethyl orthosilicate precursor($\rm TEOS-SiO_2$). Two process generations use damascene fabrication, and thethird one uses Cloisonn\'{e} fabrication. For all three, $\rm TEOS-SiO_2$exhibits a dielectric loss tangent $\tan \delta = 0.0012 \pm 0.0001$,independent of $\rm Nb$ wire width over $0.25 - 4 \: \mu m$. The $\rm Nb$ lossvaries with both the processing and the wire width. For damascene fabrication,scanning transmission electron microscopy (STEM) and energy dispersive X-rayspectroscopy (EDS) reveal that Nb oxide and Nb grain growth orientationincrease the loss above the Bardeen Cooper Schrieffer (BCS) minimum theoreticalresistance $R _{BCS}$. For Cloisonn\'{e} fabrication, the $0.25 \: \mu m$ wide$\rm Nb$ wires exhibit an intrinsic resistance $R_s = 13 \pm 1.4 \: \mu \Omega$at 10 GHz, which is below $R_{BCS} \approx 17 \: \mu \Omega$. That is arguablythe lowest resistive loss reported for $\rm Nb$.

Disentangling superconductor and dielectric microwave losses in  sub-micron $\rm Nb$/$\rm TEOS-SiO_2$ interconnects using a multi-mode  microstrip resonator