A low-disorder Metal-Oxide-Silicon double quantum dot

Abstract

One of the biggest challenges impeding the progress of Metal-Oxide-Silicon (MOS) quantum dot devices is the presence of disorder at the Si/SiO${}_2$ interface which interferes with controllably confining single and few electrons. In this work we have engineered a low-disorder MOS quantum double-dot device with critical electron densities, i.e. the lowest electron density required to support a conducting pathway, approaching critical electron densities reported in high quality Si/SiGe devices and commensurate with the lowest critical densities reported in any MOS device. Utilizing a nearby charge sensor, we show that the device can be tuned to the single-electron regime where charging energies of $\approx$8 meV are measured in both dots, consistent with the lithographic size of the dot. Probing a wide voltage range with our quantum dots and charge sensor, we detect three distinct electron traps, corresponding to a defect density consistent with the ensemble measured critical density. Low frequency charge noise measurements at 300 mK indicate a 1/$f$ noise spectrum of 3.4 $\mu$eV/Hz${}^{1/2}$ at 1 Hz and magnetospectroscopy measurements yield a valley splitting of 110$\pm$26 $\mu$eV. This work demonstrates that reproducible MOS spin qubits are feasible and represents a platform for scaling to larger qubit systems in MOS.

arXiv comment16 pages, 5 figures

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Cited by in corpus (7)

• Charge detection in an array of CMOS quantum dots
• Quantum transport properties of industrial ${}^{28}$Si/${}^{28}$SiO${}_2$
• A silicon singlet-triplet qubit driven by spin-valley coupling
• Modelling semiconductor spin qubits and their charge noise environment for quantum gate fidelity estimation
• Interplay of charge noise and coupling to phonons in adiabatic electron transfer between quantum dots
• Scalable on-chip multiplexing of silicon single and double quantum dots
• Improving mobility of silicon metal-oxide-semiconductor devices for quantum dots by high vacuum activation annealing