Methods and structures corresponding to superconducting apparatus including superconducting layers and traces are provided. A method for forming a superconducting apparatus includes forming a first dielectric layer on a substrate by depositing a first dielectric material on the substrate and curing the first dielectric material at a first temperature. The method further includes forming a first superconducting layer comprising a first set of patterned superconducting traces on the first dielectric layer. The method further includes forming a second dielectric layer on the first superconducting layer by depositing a second dielectric material on the first superconducting layer and curing the second dielectric material at a second temperature, where the second temperature is lower than the first temperature. The method further includes forming a second superconducting layer comprising a second set of patterned superconducting traces on the second dielectric layer.

Various techniques and apparatus permit fabrication of superconductive circuits. A superconducting integrated circuit comprising a superconducting stud via, a kinetic inductor, and a capacitor may be formed. Forming a superconducting stud via in a superconducting integrated circuit may include masking with a hard mask and masking with a soft mask. Forming a superconducting stud via in a superconducting integrated circuit may include depositing a dielectric etch stop layer. Interlayer misalignment in the fabrication of a superconducting integrated circuit may be measured by an electrical vernier. Interlayer misalignment in the fabrication of a superconducting integrated circuit may be measured by a chain of electrical verniers and a Wheatstone bridge. A superconducting integrated circuit with three or more metal layers may include an enclosed, matched, on-chip transmission line. A metal wiring layer in a superconducting integrated circuit may be encapsulated.

Disclosed herein are quantum dot devices, as well as related computing devices and methods. For example, in some embodiments, a quantum dot device may include: a quantum well stack structure of a quantum dot device, wherein the quantum well stack structure includes an insulating material to define multiple rows of quantum dot formation regions; and a gate that extends over multiple ones of the rows.

A method is provided of forming a superconductor device interconnect structure. The method comprises forming a first dielectric layer overlying a substrate and forming a superconducting interconnect element in the first dielectric layer. The superconducting interconnect element includes a top surface aligned with a top surface of the first dielectric layer to form a first interconnect layer. The superconductor device interconnect structure is moved into a dielectric deposition chamber. The method further comprises performing a cleaning process on a top surface of the first interconnect layer in the dielectric deposition chamber to remove oxidization from a top surface of the first interconnect layer, and depositing a second dielectric layer over the first interconnect layer in the dielectric deposition chamber.

An integrated circuit is provided that comprises a first ground plane associated with a first set of circuits that have a first operational temperature requirement, and a second ground plane associated with a second set of circuits that have a second operational temperature requirement that is higher than the first operational temperature requirement. The second ground plane is substantially thermally isolated from the first ground plane. A superconducting coupler electrically couples the first ground plane and the second ground plane while maintaining relative thermal isolation between the first ground plane and the second ground plane.

Devices and methods that can facilitate hybrid under-bump metallization components are provided. According to an embodiment, a device can comprise an under-bump metallization component that can comprise a superconducting interconnect component and a solder wetting component. The device can further comprise a solder bump that can be coupled to the superconducting interconnect component and the solder wetting component. In some embodiments, the superconducting interconnect component can comprise a hermetically sealed superconducting interconnect component.

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 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 method for forming a superconducting interconnect structure, comprising: providing a substrate, forming a superconductive layer, forming a layer of a first dielectric material, removing parts of the layer of the first dielectric material and of the superconductive layer so as to form a pattern comprising a first set of line structures comprising: a first set of superconductive line structures, and a first set of line structures made of the first dielectric material, forming a second dielectric material between the line structures of the first set, forming a layer formed of a third dielectric material, providing a patterned mask, transferring the pattern into the first dielectric material and into the layer formed of the third dielectric material, so as to form the at least one via hole, removing the patterned mask, and forming a superconductive material layer so as to form at least one via.

A superconducting circuit includes a photon detector component, a second component, and a multi-taper superconducting connector shaped to reduce current crowding, the superconducting connector electrically connecting the photon detector component and the second component. The multi-taper superconducting connector includes a first taper arranged adjacent the photon detector component and a second taper arranged adjacent the second component.