Physically defined silicon triple quantum dots charged with few electrons in metal-oxide-semiconductor structures

Hiraoka, Soichiro; Horibe, Kosuke; Ishihara, Ryoichi; Oda, Shunri; Kodera, Tetsuo

doi:10.1063/5.0010906

Cited by 7 publications

(5 citation statements)

References 38 publications

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“…[ 7–13 ] Coherent manipulations of spin qubit states via all‐electrical means have now been achieved in InAs and InSb nanowire double QDs (DQDs). [ 14,15 ] Experimental efforts have been made to extending DQDs to nanowire triple quantum dots (TQDs), [ 16–21 ] which are of great importance for achieving decoherence‐free and exchange‐only qubit operations [ 22–25 ] and coherent quantum teleportation, [ 26,27 ] and for understanding rich physical phenomena, such as ground‐state charge configurations at quadruple points (QPs), [ 16–19 ] quantum cellular automata (QCA) [ 28–30 ] operations, and strong quantum correlations in Fermi–Hubbard systems. [ 5 ]…”

Section: Introductionmentioning

confidence: 99%

Charge States, Triple Points, and Quadruple Points in an InAs Nanowire Triple Quantum Dot Revealed by an Integrated Charge Sensor

Liu

et al. 2023

Adv Quantum Tech

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A serial triple quantum dot (TQD) integrated with a quantum dot (QD) charge sensor is realized from an InAs nanowire via a fine finger‐gate technique. The complex charge states and intriguing properties of the device are studied in the few‐electron regime by direct transport measurements and by charge‐sensor detection measurements. The charge stability diagram for a capacitively coupled, parallel double‐QD formed from a QD in the TQD and the sensor QD show a visible capacitance coupling between the TQD and the sensor QD, indicating a good sensitivity of the charge sensor. The charge stability diagrams of the TQD are measured by the charge sensor and the global features in the charge stability diagrams are well reproduced by the simultaneous direct transport measurements and by the simulation made based on an effective capacitance network model. The complex charge stability diagrams of the TQD are measured in detail with the integrated charge sensor in an energetically degenerate region, where all the three QDs are on or nearly on resonance, and the formations of quadruple points and of all possible eight charge states are observed. In addition, the operation of the TQD as a quantum cellular automata is demonstrated and discussed.

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Section: Introductionmentioning

confidence: 99%

Charge States, Triple Points, and Quadruple Points in an InAs Nanowire Triple Quantum Dot Revealed by an Integrated Charge Sensor

Liu

et al. 2023

Adv Quantum Tech

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“…28) In this study, we use SQD part of the PMOS silicon QD device to readout charge transition via RF reflectometry. The device we fabricated is a physically defined QD, therefore, it does not need gates to form confinement potential [29][30][31] and it has less complexity. Since it is a p-channel device and has strong SOC, it does not require additional structure for spin manipulation.…”

Section: Introductionmentioning

confidence: 99%

RF reflectometry for readout of charge transition in a physically defined p-channel MOS silicon quantum dot

Buğu

Nishiyama

Kato

et al. 2021

Jpn. J. Appl. Phys.

Self Cite

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We have embedded a physically defined p-channel MOS silicon quantum dot (QD) device into an impedance transformer RC circuit. To decrease the parasitic capacitance of the device which emerges in MOS devices that have a top gate, we fabricate a new device to reduce the device’s top gate area from 400 to 0.09 μm2. Having a smaller top gate eliminates parasitic capacitance problem preventing the RF signal from reaching QD. We show that we have fabricated a single QD properly, which is essential for RF single-electron transistor technique. We also analyze and improve the impedance matching condition and show that it is possible to perform readout of charge transition at 4.2 K by RF reflectometry. This will enable fast readout of charge and spin states.

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“…On the other hand, improving the lithography resolution is not the only requirement for wider quantum device applications, particularly in research, for processing various types of Si qubit structures. This is because some quantum devices require precisely designed nonrectilinear lines [2,15], a very dense group of lines [3,16], dot shapes [17][18][19], and so on, and these features are largely different from those of logic devices. In addition, a large number of devices are integrated into a chip with a short distance to realize quantum coupling between qubits, thereby increasing the layout density.…”

Section: Introductionmentioning

confidence: 99%

Electron beam lithography with negative tone resist for highly integrated silicon quantum bits

Kato¹,

Liu²,

Murakami³

et al. 2021

Nanotechnology

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Process technologies have been developed for electron-beam (EB) lithography aimed at silicon quantum devices and their large-scale integration. It is necessary to understand the proximity effect and construct a method for its correction to perform EB lithography of fine and complicated structures. In this study, we investigate the lithography of Si quantum devices with a point-beam EB system and a maN 2401 negative tone resist, in order to correspond to various types of device structures. We optimize temperatures for specialized pre-and post-exposure bakes for forming∼20 nm fine patterns with small line-edge roughness. Further, we demonstrated the fabrication of Si-on-insulator device patterns that have some tiny dots connected with many large wires/pads in the layout, with the careful tuning of the dose assignment. In this tuning, we used the EB process simulation to estimate the cumulative dose distribution effectively. In addition, we reproduced the experimentally obtained resist patterns via the EB process simulation after considering the mid-range effect, which is a factors in the proximity effect but is not yet deeply understood. The results of this study are expected to provide useful process technologies for EB lithography, which will help drastically accelerate the research on Si quantum devices with a high degree of freedom.

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Physically defined silicon triple quantum dots charged with few electrons in metal-oxide-semiconductor structures

Cited by 7 publications

References 38 publications

Charge States, Triple Points, and Quadruple Points in an InAs Nanowire Triple Quantum Dot Revealed by an Integrated Charge Sensor

Charge States, Triple Points, and Quadruple Points in an InAs Nanowire Triple Quantum Dot Revealed by an Integrated Charge Sensor

RF reflectometry for readout of charge transition in a physically defined p-channel MOS silicon quantum dot

Electron beam lithography with negative tone resist for highly integrated silicon quantum bits

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