Abstract: An array of quantum dot qubits (e.g., an array of spin qubits) relies on a gradient magnetic field to ensure that the qubits are separated in frequency in order to be individually addressable. Furthermore, a strong magnetic field gradient is required to electrically drive the electric dipole spin resonance (EDSR) of the qubits. Quantum dot devices disclosed herein use microcoil arrangements for providing a gradient magnetic field, the microcoil arrangements integrated on the same chip (e.g., on the same die or wafer) as quantum dot qubits themselves. Unlike previous approaches to quantum dot formation and manipulation, various embodiments of the quantum dot devices disclosed herein may enable improved control over magnetic fields and their gradients to realize better frequency targeting of individual qubits, help minimize adverse effects of charge noise on qubit decoherence and provide good scalability in the number of quantum dots included in the device.

Abstract: 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 and a plurality of linear arrays of gates above the quantum well stack to control quantum dot formation in the quantum well stack. An insulating material may be between a first linear array of gates and a second linear array of gates, the insulating material may be between individual gates in the first linear array of gates, and gate metal of the first linear array of gates may extend over the insulating material.

Abstract: 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 (111) silicon substrate, a (111) germanium quantum well layer above the substrate, and a plurality of gates above the quantum well layer. In some embodiments, a quantum dot device may include a silicon substrate, an insulating material above the silicon substrate, a quantum well layer above the insulating material, and a plurality of gates above the quantum well layer.

Abstract: 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; an insulating material disposed above the quantum well stack, wherein the insulating material includes a trench; and a gate metal disposed on the insulating material and extending into the trench.

Abstract: Disclosed herein are single electron transistor (SET) devices, and related methods and devices. In some embodiments, a SET device may include: first and second source/drain (S/D) electrodes; a plurality of islands, disposed between the first and second S/D electrodes; and dielectric material disposed between adjacent ones of the islands, between the first S/D electrode and an adjacent one of the islands, and between the second S/D electrode and an adjacent one of the islands.

Abstract: Disclosed herein are quantum dot devices with conductive liners, as well as related computing devices and methods. For example, in some embodiments, a quantum dot device may include a base, a first fin extending from the base, a second fin extending from the base, a conductive material between the first fin and the second fin, and a dielectric material between the conductive material and the first fin.

Abstract: A quantum dot device is disclosed that includes a quantum well stack, a first and a second plunger gates above the quantum well stack, and a passive barrier element provided in a portion of the quantum well stack between the first and the second plunger gates. The passive barrier element may serve as means for localizing charge in the quantum dot device and may be used to replace charge localization control by means of a barrier gate. In general, a quantum dot device with a plurality of plunger gates provided over a given quantum well stack may include a respective passive barrier element between any, or all, of adjacent plunger gates in the manner as described for the first and second plunger gates.

Abstract: 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 including a quantum well layer; a plurality of gates disposed above the quantum well stack, wherein at least two of the gates are spaced apart in a first dimension above the quantum well stack, at least two of the gates are spaced apart in a second dimension above the quantum well stack, and the first and second dimensions are perpendicular; and an insulating material disposed above the quantum well stack, wherein the insulating material extends between at least two of the gates spaced apart in the first dimension, and the insulating material extends between at least two of the gates spaced apart in the second dimension.

Abstract: One superconducting qubit device package disclosed herein includes a die having a first face and an opposing second face, and a package substrate having a first face and an opposing second face. The die includes a quantum device including a plurality of superconducting qubits and a plurality of resonators on the first face of the die, and a plurality of conductive pathways coupled between conductive contacts at the first face of the die and associated ones of the plurality of superconducting qubits or of the plurality of resonators. The second face of the package substrate also includes conductive contacts. The device package further includes first level interconnects disposed between the first face of the die and the second face of the package substrate, coupling the conductive contacts at the first face of the die with associated conductive contacts at the second face of the package substrate.

Abstract: Disclosed herein are quantum dot devices and techniques. In some embodiments, a quantum computing processing device may include a quantum well stack, an array of quantum dot gate electrodes above the quantum well stack, and an associated array of selectors above the array of quantum dot gate electrodes. The array of quantum dot gate electrodes and the array of selectors may each be arranged in a grid.

Abstract: Disclosed herein are quantum dot devices, as well as related computing devices and methods. For example, in some embodiments, a quantum processing device may include a quantum well stack, the quantum well stack includes a quantum well layer, the quantum processing device further includes a plurality of gates above the quantum well stack to control quantum dot formation in the quantum well stack, and (1) gate metal of individual gates of the array of gates is tapered so as to narrow farther from the quantum well stack or (2) top surfaces of gate metal of individual gates of the array of gates are dished.

Abstract: A quantum dot device is disclosed that includes a fin and a gate above the fin. The fin may extend away from a base and include a quantum well stack in which one or more quantum dots may be formed during operation of the quantum dot device. The gate may include a gate electrode material having a first portion and a second portion, where the first portion is above the quantum well stack and the second portion is a portion that is not above the quantum well stack and is separated from the base by an insulating material. The quantum dot device may further include a metal structure between the second portion of the gate electrode material and the base, forming a portion of a diode provided in series with the gate, which diode may provide at least some ESD protection for the quantum dot device.

Abstract: 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 base; a fin extending away from the base, wherein the fin includes a quantum well layer; an insulating material at least partially above the fin, wherein the insulating material includes a trench above the fin; and a gate metal on the insulating material and extending into the trench.

Abstract: 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; a first gate and an adjacent second gate above the quantum well stack; and a multi-spacer between the first gate and the second gate, wherein the multi-spacer includes a first spacer and a second spacer different from the first spacer, and the first spacer is at least partially between the quantum well stack and the second spacer.

Abstract: 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; a first gate above the quantum well stack, wherein the first gate includes a first gate metal and a first gate dielectric layer; and a second gate above the quantum well stack, wherein the second gate includes a second gate metal and a second gate dielectric layer, and the second gate dielectric layer extends over the first gate.

Abstract: 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 including a quantum well layer; a first gate above the quantum well stack, wherein the first gate includes a first gate metal; and a second gate above the quantum well stack, wherein the second gate includes a second gate metal, and a material structure of the second gate metal is different from a material structure of the first gate metal; wherein the quantum well layer has a first strain under the first gate, a second strain under the second gate, and the first strain is different from the second strain.

Abstract: 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; a first gate above the quantum well stack, wherein the first gate includes a first gate metal and a first gate dielectric; and a second gate above the quantum well stack, wherein the second gate includes a second gate metal and a second gate dielectric, and the first gate is at least partially between a portion of the second gate and the quantum well stack.

Abstract: Disclosed herein are lateral gate material arrangements for 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; and a gate above the quantum well stack, wherein the gate includes a gate electrode, the gate electrode includes a first material proximate to side faces of the gate and a second material proximate to a center of the gate, and the first material has a different material composition than the second material.

Abstract: Embodiments of the present disclosure describe a method of fabricating spin qubit device assemblies that utilize dopant-based spin qubits, i.e. spin qubit devices which operate by including a donor or an acceptor dopant atom in a semiconductor host layer. The method includes, first, providing a pair of gate electrodes over a semiconductor host layer, and then providing a window structure between the first and second gate electrodes, the window structure being a continuous solid material extending between the first and second electrodes and covering the semiconductor host layer except for an opening through which a dopant atom is to be implanted in the semiconductor host layer. By using a defined gate-first process, the method may address the scalability challenges and create a deterministic path for fabricating dopant-based spin qubits in desired locations, promoting wafer-scale integration of dopant-based spin qubit devices for use in quantum computing devices.

Abstract: 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; a first gate above the quantum well stack, wherein the first gate includes a first gate metal and a first gate dielectric; and a second gate above the quantum well stack, wherein the second gate includes a second gate metal and a second gate dielectric, and the first gate is at least partially between a portion of the second gate and the quantum well stack.