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 method includes: providing a device having a first layer and a second layer in contact with a surface of the first layer, in which the second layer includes a first superconductor material; forming a buffer material on the second layer to form an etch buffer layer, in which an etch rate selectivity of the buffer material relative to the second layer upon exposure to a photoresist developer is such that the underlying second layer is not etched during exposure of the buffer layer to the photoresist developer; depositing and removing a selected portion of a resist layer to uncover a first portion of the etch buffer layer, wherein removing the selected portion of the resist layer comprises applying the photoresist developer to the selected portion of the resist layer.

A capacitive coupling device (superconducting C-coupler) includes a trench formed through a substrate, from a backside of the substrate, reaching a depth in the substrate, substantially orthogonal to a plane of fabrication on a frontside of the substrate, the depth being less than a thickness of the substrate. A superconducting material is deposited as a continuous conducting via layer in the trench with a space between surfaces of the via layer in the trench remaining accessible from the backside. A superconducting pad is formed on the frontside, the superconducting pad coupling with a quantum logic circuit element fabricated on the frontside. An extension of the via layer is formed on the backside. The extension couples to a quantum readout circuit element fabricated on the backside.

A semiconductor structure and methods of forming the semiconductor structure generally includes providing a thermocompression bonded superconducting metal layer sandwiched between a first silicon substrate and a second silicon substrate. The second substrate includes a plurality of through silicon vias to the thermocompression bonded superconducting metal layer. A second superconducting metal is electroplated into the through silicon vias using the thermocompression bonded superconducting metal layer as a bottom electrode during the electroplating process, wherein the filling is from the bottom upwards.

A low-noise wide band amplifier is realized utilizing a superconductor-insulator-superconductor (SIS) junction, quasiparticle frequency mixers connected in tandem or in cascade, a first quasiparticle mixer performs first frequency mixing with use of a first local signal having a frequency not less than twice a frequency of an input signal to the first quasiparticle mixer, a second quasiparticle mixer performs second frequency mixing with use of a second local signal having a frequency not more than twice a frequency of an input signal to the second quasiparticle mixer, and signal amplification is performed through frequency conversion by extracting, from among a plurality of signals generated with the first and the second frequency mixing, a signal in a frequency band not more than a frequency band of the signal before the first frequency mixing and the second frequency mixing, using a transmission line or a filter.

A capacitive coupling device (superconducting C-coupler) includes a trench formed through a substrate, from a backside of the substrate, reaching a depth in the substrate, substantially orthogonal to a plane of fabrication on a frontside of the substrate, the depth being less than a thickness of the substrate. A superconducting material is deposited as a continuous conducting via layer in the trench with a space between surfaces of the via layer in the trench remaining accessible from the backside. A superconducting pad is formed on the frontside, the superconducting pad coupling with a quantum logic circuit element fabricated on the frontside. An extension of the via layer is formed on the backside. The extension couples to a quantum readout circuit element fabricated on the backside.

A substrate processing method is described for forming a titanium nitride material that may be used for superconducting metallization or work function adjustment applications. The substrate processing method includes depositing by vapor phase deposition at least one monolayer of a first titanium nitride film on a substrate, and treating the first titanium nitride film with plasma excited hydrogen-containing gas, where the first titanium nitride film is polycrystalline and the treating increases the (200) crystallographic texture of the first titanium nitride film. The method further includes depositing by vapor phase deposition at least one monolayer of a second titanium nitride film on the treated at least one monolayer of the first titanium nitride film, and treating the at least one monolayer of the second titanium nitride film with plasma excited hydrogen-containing gas.

A capacitive coupling device (superconducting C-coupler) includes a trench formed through a substrate, from a backside of the substrate, reaching a depth in the substrate, substantially orthogonal to a plane of fabrication on a frontside of the substrate, the depth being less than a thickness of the substrate. A superconducting material is deposited as a continuous conducting via layer in the trench with a space between surfaces of the via layer in the trench remaining accessible from the backside. A superconducting pad is formed on the frontside, the superconducting pad coupling with a quantum logic circuit element fabricated on the frontside. An extension of the via layer is formed on the backside. The extension couples to a quantum readout circuit element fabricated on the backside.

A semiconductor structure and methods of forming the semiconductor structure generally includes providing a thermocompression bonded superconducting metal layer sandwiched between a first silicon substrate and a second silicon substrate. The second substrate includes a plurality of through silicon vias to the thermocompression bonded superconducting metal layer. A second superconducting metal is electroplated into the through silicon vias using the thermocompression bonded superconducting metal layer as a bottom electrode during the electroplating process, wherein the filling is from the bottom upwards.

The present invention provides a process and structure of microfabricated air bridges for planar microwave resonator circuits. In an embodiment, the invention includes depositing a superconducting film on a surface of a base material, where the superconducting film is formed with a compressive stress, where the compressive stress is higher than a critical buckling stress of a defined structure, etching an exposed area of the superconducting film, thereby creating the at least one bridge, etching the base material, thereby forming a gap between the at least one bridge and the base material, depositing the at least one metal line on at least part of the superconducting film and at least part of the base material, where the at least one metal line runs under the bridge.