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dc.contributor.authorMichniewicz, John
dc.date.accessioned2022-04-13T16:04:21Z
dc.date.available2022-04-13T16:04:21Z
dc.date.submitted2021-12-24
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/336062
dc.description.abstractThe main challenge in quantum computing is not how to make qubits, but how to make a lot of them. Especially, the one-qubit-one-input approach is unsustainable for higher numbers. This issue has already been resolved in classical computing, and I investigate a similar solution for quantum. I evaluate the expansibility prospects of a multiplexing chip: a two-dimensional access array, designed to combat this very problem. First, I characterize on-chip integrated transistors. I list their standard transport parameters, such as threshold voltage, subthreshold swing, and drain induced barrier lowering. Additionally, I report Coulomb oscillations and the formation of quantum dots in 40 nm commercially-available MOSFET devices. I benchmark those against a finFET of the same dimensions, designed for quantum operation. I reflect on the readiness of industrial CMOS devices for use in quantum computing. Then, I assess the operation of control transistors in a memory cell structure. I analyze retention times and comment on their usability for a refresh mechanism and time-multiplexed access to quantum information. Afterward, I demonstrate the mechanism of gate-based reflectometry readout. I detail the RF circuitry, including the room-temperature equipment, and the on-chip analog LC resonators. I present my findings on tuning individual parameters, and their impact on the signal quality, quantitatively depicted by the signal-to-noise ratio and Q factor comparison. I explain the difficulties faced with managing the readout at several GHz, and some other challenges, including parasitics-induced frequency shift and overlap. Finally, I demonstrate time- and frequency-domain multiplexing for an integrated array, as well as two different cointegrated architectures.
dc.rightsAttribution 4.0 International (CC BY 4.0)
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subjectquantum
dc.subjectquantum computing
dc.subjectspinqubits
dc.subjectsilicon
dc.subjectreflectometry
dc.subjectgate-based sensing
dc.subjectqubit
dc.subjectqubits
dc.subjectquantum dot
dc.subjectmultiplexing
dc.subjectFDM
dc.subjectTDM
dc.titleExpansibility Evaluation of a Two-dimensional Access Array for Quantum Computing
dc.typeThesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnameDoctor of Philosophy (PhD)
dc.publisher.institutionUniversity of Cambridge
dc.date.updated2022-04-04T09:25:33Z
dc.identifier.doi10.17863/CAM.83492
rioxxterms.licenseref.urihttps://creativecommons.org/licenses/by/4.0/
rioxxterms.typeThesis
cam.supervisorCiccarelli, Chiara
cam.depositDate2022-04-04
pubs.licence-identifierapollo-deposit-licence-2-1
pubs.licence-display-nameApollo Repository Deposit Licence Agreement


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Attribution 4.0 International (CC BY 4.0)
Except where otherwise noted, this item's licence is described as Attribution 4.0 International (CC BY 4.0)