On a first superconducting layer deposited on a first surface of a substrate, a first component of a resonator is pattered. On a second superconducting layer deposited on a second surface of the substrate, a second component of the resonator is patterned. The first surface and the second surface are disposed relative to each other in a non-co-planar disposition. In the substrate, a recess is created, the recess extending from the first superconducting layer to the second superconducting layer. On an inner surface of the recess, a third superconducting layer is deposited, the third superconducting layer forming a superconducting path between the first superconducting layer and the second superconducting layer. Excess material of the third superconducting layer is removed from the first surface and the second surface, forming a completed through-silicon via (TSV).

A superconductor device according to some embodiments comprises a superconductor stack, which includes a superconductor layer and a silicon cap layer over the superconductor layer, the cap layer including amorphous silicon. The superconductor device further comprises a metal contact over a portion of the silicon cap layer and electrically-coupled to the superconductor layer. The metal contact comprises a core including a first metal, and an outer layer around the core that includes a second metal. The portion of the silicon cap layer is converted from silicon to a conductive compound including the second metal to provide low-resistance electrical coupling between the superconductor layer and the metal contact. The superconductor device further comprises a waveguide, and the first portion of the cap layer under the metal contact is at a sufficient lateral distance from the waveguide to prevent optical coupling between the metal contact and the waveguide.

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 device includes a first semiconductor layer; a portion of a second semiconductor layer disposed on the first semiconductor layer; and a third semiconductor layer including a first region disposed on the portion of the second semiconductor layer and a second region disposed on the first semiconductor layer. A thickness of the first region is less than a predefined thickness. The device also includes an etch stop layer disposed on the third semiconductor layer; a plurality of distinct portions of a fourth semiconductor layer disposed on the etch stop layer and exposing one or more distinct portions of the etch stop layer over the portion of the second semiconductor layer; and a plurality of distinct portions of a superconducting layer disposed on the plurality of distinct portions of the fourth semiconductor layer and the exposed one or more distinct portions of the etch stop layer.

A physical vapor deposition system includes a chamber, three target supports to targets, a movable shield positioned having an opening therethrough, a workpiece support to hold a workpiece in the chamber, a gas supply to deliver nitrogen gas and an inert gas to the chamber, a power source, and a controller. The controller is configured to move the shield to position the opening adjacent each target in turn, and at each target cause the power source to apply power sufficient to ignite a plasma in the chamber to cause deposition of a buffer layer, a device layer of a first material that is a metal nitride suitable for use as a superconductor at temperatures above 8 K on the buffer layer, and a capping layer, respectively.

A structure including a metal nitride layer is formed on a workpiece by pre-conditioning a chamber that includes a metal target by flowing nitrogen gas and an inert gas at a first flow rate ratio into the chamber and igniting a plasma in the chamber before placing the workpiece in the chamber, evacuating the chamber after the preconditioning, placing the workpiece on a workpiece support in the chamber after the preconditioning, and performing physical vapor deposition of a metal nitride layer on the workpiece in the chamber by flowing nitrogen gas and the inert gas at a second flow rate ratio into the chamber and igniting a plasma in the chamber. The second flow rate ratio is less than the first flow rate ratio.

Described herein are structures that include interconnects for providing electrical connectivity in superconducting quantum circuits. In one aspect of the present disclosure, a structure includes a first and a second interconnects provided over a surface of an interconnect support layer on which superconducting qubits are provided (which could be a substrate), a lower interconnect provided below such surface, and vias for providing electrical interconnection between the lower interconnect and each of the first and second interconnects. The lower interconnect includes a material of the interconnect support layer doped to be superconductive. Providing below-plane interconnects in superconducting quantum circuits allows realizing superconducting and mechanically stable interconnects. Implementing below-plane interconnects by doping the interconnect support layer, material for which could be selected, allows minimizing the amount of spurious TLS's in the areas surrounding below-plane interconnects. Methods for fabricating such structures are disclosed as well.

Described herein are structures that include interconnects for providing electrical connectivity in superconducting quantum circuits. One structure includes a first and a second interconnects provided over a surface of an interconnect support layer, e.g. a substrate, on which superconducting qubits are provided, a lower interconnect provided below such surface (i.e. below-plane interconnect), and vias for providing electrical interconnection between the lower interconnect and each of the first and second interconnects. Providing below-plane interconnects in superconducting quantum circuits allows realizing superconducting and mechanically stable interconnects. Implementing below-plane interconnects by bonding of two substrates, material for which could be selected, allows minimizing the amount of spurious two-level systems in the areas surrounding below-plane interconnects while allowing different choices of materials to be used. Methods for fabricating such structures are disclosed as well.

An integrated, superconducting imaging sensor may be formed from a single, meandering nanowire. The sensor is capable of single-photon (or single-event) detection and imaging with 10 micron spatial resolution and sub-100-picosecond temporal resolution. The sensor may be readily scaled to large areas.

A superconducting integrated circuit includes at least one superconducting resonator, including a substrate, a conductive layer disposed over a surface of the substrate with the conductive layer including at least one conductive material including a substantially low stress polycrystalline Titanium Nitride (TiN) material having an internal stress less than about two hundred fifty MPa (magnitude) such that the at least one superconducting resonator and/or qubit (hereafter called device) is provided as a substantially high quality factor, low loss superconducting device.