A method and a device for preparing an inductance element, an inductance element, and a superconducting circuit are provided. The method includes acquiring a compound for preparing an inductance element, a superconducting coherence length and a magnetic field penetration depth of the compound meeting a preset condition; and annealing the compound to cause decomposition between a non-superconductor phase and a superconductor phase in the compound to generate the inductance element, the kinetic inductance of the inductance element being greater than the geometric inductance of the inductance element.

A cryo-compatible quantum computing arrangement includes a microelectronic quantum computing component having a substrate structure, a plurality of first contact elements and a plurality of conductive feedthroughs through the substrate structure, wherein the conductive feedthroughs are electrically connected on a first main surface area of the substrate structure to associated first contact elements of the microelectronic quantum computing component, and a further microelectronic component having a plurality of second contact elements, wherein on a second main surface area of the substrate structure, the conductive feedthroughs are electrically connected to associated second contact elements of the further microelectronic component, and wherein the conductive feedthroughs each include, between the first and second contact elements, a layer element including a first material that is superconducting at a quantum computing operating temperature, and a filling element including a second material that is electrically conductive.

An electronic device includes a first surface and a second surface opposite the first surface and intended to connect a first electronic component to a second electronic component located on the first surface by at least one conductor track, the conductor track including a plurality of sections disposed one after the other in such a way as to form the conductor track, each section being constituted of a superconducting material chosen in such a way as to form with the section that follows it, if such a section exists, and the section that precedes it, if such a section exists, an acoustic mismatching interface (or Kapitza interface).

A quantum computing device includes a first chip having a first substrate and one or more qubits disposed on the first substrate. Each of the one or more qubits has an associated resonance frequency. The quantum computing device further includes a second chip having a second substrate and at least one conductive surface disposed on the second substrate opposite the one or more qubits. The at least one conductive surface has at least one dimension configured to adjust the resonance frequency associated with at least one of the one or more qubits to a determined frequency adjustment value.

A superconducting device includes a substrate, a metal oxide or metal oxynitride seed layer on the substrate, and a metal nitride superconductive layer disposed directly on the seed layer. The seed layer is an oxide or oxynitride of a first metal, and the superconductive layer is a nitride of a different second metal.

Techniques and methods to form smooth metal layers deposited onto selected surfaces of Josephson junction devices are provided. For example, one or more embodiments described herein can comprise depositing a layer of a first material comprising metal atom species on a selected surface of a device layer; depositing a layer of a second material on a surface of the layer of first material; and performing plasma etching on the layer of second material and the layer of first material to form an etched surface of the layer of first material that is smoother than the surface of the layer of first material, as deposited.

A superconducting nanowire single photon detector (SNSPD) device includes a substrate having a top surface, an optical waveguide on the top surface of the substrate to receive light propagating substantially parallel to the top surface of the substrate, a seed layer of metal nitride on the optical waveguide, and a superconductive wire on the seed layer. The superconductive wire is a metal nitride different from the metal nitride of the seed layer and is optically coupled to the optical waveguide.

A vertical Josephson Junction (JJ) qubit device that is fabricated from crystalline silicon material is provided. The JJ device has a substrate of epitaxial silicon, a lower superconducting electrode that is a superconducting region of the epitaxial silicon and an upper superconducting electrode of a metallic superconductor. The JJ device also has a junction layer. A section of the junction layer between the lower and upper superconducting electrodes forms a junction of the JJ device. Resonator and/or capacitor wiring of the JJ device is also fabricated using the metallic superconductor. The superconducting region is epitaxial silicon that is doped or implanted with boron or gallium. The substrate, the junction layer, and the implanted epitaxial silicon share a contiguous crystalline structure.

A method of forming a composite crystalline nitride structure is provided. The method includes depositing a first crystalline nitride layer on a substrate, patterning the first crystalline nitride layer to form a patterned crystalline nitride layer having a top surface and that includes undulations, annealing the patterned crystalline nitride layer at a temperature between 300° C. to 850° C. to form an annealed patterned crystalline nitride layer, and depositing a second crystalline nitride layer on the annealed patterned crystalline nitride layer. The second crystalline nitride layer is lattice-matched to the underlying annealed patterned crystalline nitride layer to within 2%, thereby forming the composite crystalline nitride structure.

A device includes: a substrate; a first superconductor layer on the substrate, the first superconductor layer having a first kinetic inductance; and a second superconductor layer on the first superconductor layer, the second superconductor layer having a second kinetic inductance that is lower than the first kinetic inductance, in which the second superconductor layer covers the first superconductor layer such that the second superconductor layer and the first superconductor layer have a same footprint, with the exception of at least a first region where the second superconductor layer is omitted so that the first superconductor layer and the second superconductor layer form a circuit element having a predetermined circuit parameter.