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.

A method for manufacturing superconducting films. The method includes: heating a first atmosphere environment where a first superconducting film is located from a first temperature to a second temperature, so that the first superconducting film is in a second atmosphere environment, the first superconducting film being a superconducting material deposited on a substrate; continuously introducing hydrogen atoms into the second atmosphere environment and maintaining for a predetermined duration after the second atmosphere environment reaches the second temperature, so that the first superconducting film is in a third atmosphere environment and micro-scale crystal structure defects of the first superconducting film are filled with the hydrogen atoms, the second temperature being configured to maintain a free state of the hydrogen atoms; and cooling the third atmosphere environment from the second temperature to a third temperature less than the first temperature after the predetermined duration to manufacture a second superconducting film.

Materials and methods are disclosed for fabricating superconducting integrated circuits for quantum computing at millikelvin temperatures, comprising both quantum circuits and classical control circuits, which may be located on the same integrated circuit or on different chips of a multi-chip module. The materials may include components that reduce defect densities and increase quantum coherence times. Multilayer fabrication techniques provide low-power and a path to large scale computing systems. An integrated circuit system for quantum computing is provided, comprising: a substrate; a kinetic inductance layer having a kinetic inductance of at least 5 pH/square; a plurality of stacked planarized superconducting layers and intervening insulating layers, formed into a plurality of Josephson junctions having a critical current of less than 100 ?A/?m.sup.2; and a resistive layer that remains non-superconducting at a temperature below 1 K, configured to damp the plurality of Josephson junctions.

A cryogenic electronic package includes a first superconducting multi-chip module (SMCM), a superconducting interposer, a second SMCM and a superconducting semiconductor structure. The interposer is disposed over and coupled to the first SMCM, the second SMCM is disposed over and coupled to the interposer, and the superconducting semiconductor structure is disposed over and coupled to the second SMCM. The second SMCM and the superconducting semiconductor structure are electrically coupled to the first SMCM through the interposer. A method of fabricating a cryogenic electronic package is also provided.

A technique relates to a structure. A first surface includes an inductive element of a resonator. A second surface includes a first portion of a capacitive element of the resonator and at least one qubit. A second portion of the capacitive element of the resonator is on the first surface.

Vertically integrated superconductor/semiconductor heterostructures that comprise the necessary components of a quantum computer, which could enable integrated on-chip quantum computing at millikelvin temperatures, are disclosed.

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 technique relates to a structure. A first surface includes an inductive element of a resonator. A second surface includes a first portion of a capacitive element of the resonator and at least one qubit. A second portion of the capacitive element of the resonator is on the first surface.

A transistor structure, includes a buffer layer and a quantum well channel layer on top of the buffer layer. There is a barrier layer on top of the channel layer. There is a drain contact on a channel stack. A source contact is on a channel stack. A gate structure is located between the source contact and drain contact, comprising: an active gate portion having a bottom surface in contact with a bottom surface of the source and the drain contacts. A superconducting portion of the gate structure is in contact with, and adjacent to, an upper part of the active gate portion.