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Yang-Keathley Y, Maloney SA, Hastings JT. Real-time dose control for electron-beam lithography. NANOTECHNOLOGY 2021; 32:095302. [PMID: 33197908 DOI: 10.1088/1361-6528/abcaca] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Shot-to-shot, or pixel-to-pixel, dose variation during electron-beam lithography is a significant practical and fundamental problem. Dose variations associated with charging, electron source instability, optical system drift, and ultimately shot noise in the e-beam itself conspire to critical dimension variability, line width/edge roughness, and limited throughput. It would be an important improvement to e-beam based patterning technology if real-time feedback control of electron-dose were provided so that pattern quality and throughput would be improved beyond the shot noise limit. In this paper, we demonstrate control of e-beam dose based on the measurement of electron arrival at the sample where patterns are written, rather than from the source or another point in the electron optical column. Our results serve as the first steps towards real-time dose control and eventually overcoming the shot noise.
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Affiliation(s)
- Yugu Yang-Keathley
- Department of Electrical and Computer Engineering, Wentworth Institute of Technology, Boston, MA 02115, United States of America. Department of Electrical and Computer Engineering, University of Kentucky, Lexington, KY 40506, United States of America
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Rudolph M, Sarabi B, Murray R, Carroll MS, Zimmerman NM. Long-term drift of Si-MOS quantum dots with intentional donor implants. Sci Rep 2019; 9:7656. [PMID: 31114008 PMCID: PMC6529408 DOI: 10.1038/s41598-019-43995-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 04/27/2019] [Indexed: 11/08/2022] Open
Abstract
Charge noise can be detrimental to the operation of quantum dot (QD) based semiconductor qubits. We study the low-frequency charge noise by charge offset drift measurements for Si-MOS devices with intentionally implanted donors near the QDs. We show that the MOS system exhibits non-equilibrium drift characteristics, in the form of transients and discrete jumps, that are not dependent on the properties of the donor implants. The equilibrium charge noise indicates a 1/f noise dependence, and a noise strength as low as [Formula: see text], comparable to that reported in more model GaAs and Si/SiGe systems (which have also not been implanted). We demonstrate that implanted qubits, therefore, can be fabricated without detrimental effects on long-term drift or 1/f noise for devices with less than 50 implanted donors near the qubit.
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Affiliation(s)
- M Rudolph
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - B Sarabi
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - R Murray
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - M S Carroll
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Neil M Zimmerman
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.
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Pacheco JL, Singh M, Perry DL, Wendt JR, Ten Eyck G, Manginell RP, Pluym T, Luhman DR, Lilly MP, Carroll MS, Bielejec E. Ion implantation for deterministic single atom devices. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:123301. [PMID: 29289172 DOI: 10.1063/1.5001520] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We demonstrate a capability of deterministic doping at the single atom level using a combination of direct write focused ion beam and solid-state ion detectors. The focused ion beam system can position a single ion to within 35 nm of a targeted location and the detection system is sensitive to single low energy heavy ions. This platform can be used to deterministically fabricate single atom devices in materials where the nanostructure and ion detectors can be integrated, including donor-based qubits in Si and color centers in diamond.
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Affiliation(s)
- J L Pacheco
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - M Singh
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - D L Perry
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - J R Wendt
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - G Ten Eyck
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - R P Manginell
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - T Pluym
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - D R Luhman
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - M P Lilly
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - M S Carroll
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - E Bielejec
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
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Harvey-Collard P, Jacobson NT, Rudolph M, Dominguez J, Ten Eyck GA, Wendt JR, Pluym T, Gamble JK, Lilly MP, Pioro-Ladrière M, Carroll MS. Coherent coupling between a quantum dot and a donor in silicon. Nat Commun 2017; 8:1029. [PMID: 29044099 PMCID: PMC5715091 DOI: 10.1038/s41467-017-01113-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 08/18/2017] [Indexed: 11/30/2022] Open
Abstract
Individual donors in silicon chips are used as quantum bits with extremely low error rates. However, physical realizations have been limited to one donor because their atomic size causes fabrication challenges. Quantum dot qubits, in contrast, are highly adjustable using electrical gate voltages. This adjustability could be leveraged to deterministically couple donors to quantum dots in arrays of qubits. In this work, we demonstrate the coherent interaction of a 31P donor electron with the electron of a metal-oxide-semiconductor quantum dot. We form a logical qubit encoded in the spin singlet and triplet states of the two-electron system. We show that the donor nuclear spin drives coherent rotations between the electronic qubit states through the contact hyperfine interaction. This provides every key element for compact two-electron spin qubits requiring only a single dot and no additional magnetic field gradients, as well as a means to interact with the nuclear spin qubit. In silicon, quantum information can be stored in donors or quantum dots, each with its advantages and limitations—particularly in terms of fabrication. Here the authors coherently couple a phosphorous donor’s electron spin to a quantum dot, encoding information in the hybrid two-electron system’s state.
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Affiliation(s)
- Patrick Harvey-Collard
- Département de Physique et Institut Quantique, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1. .,Sandia National Laboratories, Albuquerque, NM, 87185, USA.
| | - N Tobias Jacobson
- Center for Computing Research, Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Martin Rudolph
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | | | | | - Joel R Wendt
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Tammy Pluym
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - John King Gamble
- Center for Computing Research, Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Michael P Lilly
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Michel Pioro-Ladrière
- Département de Physique et Institut Quantique, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1.,Quantum Information Science Program, Canadian Institute for Advanced Research, Toronto, ON, Canada, M5G 1Z8
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van Donkelaar J, Yang C, Alves ADC, McCallum JC, Hougaard C, Johnson BC, Hudson FE, Dzurak AS, Morello A, Spemann D, Jamieson DN. Single atom devices by ion implantation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:154204. [PMID: 25783169 DOI: 10.1088/0953-8984/27/15/154204] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
To expand the capabilities of semiconductor devices for new functions exploiting the quantum states of single donors or other impurity atoms requires a deterministic fabrication method. Ion implantation is a standard tool of the semiconductor industry and we have developed pathways to deterministic ion implantation to address this challenge. Although ion straggling limits the precision with which atoms can be positioned, for single atom devices it is possible to use post-implantation techniques to locate favourably placed atoms in devices for control and readout. However, large-scale devices will require improved precision. We examine here how the method of ion beam induced charge, already demonstrated for the deterministic ion implantation of 14 keV P donor atoms in silicon, can be used to implant a non-Poisson distribution of ions in silicon. Further, we demonstrate the method can be developed to higher precision by the incorporation of new deterministic ion implantation strategies that employ on-chip detectors with internal charge gain. In a silicon device we show a pulse height spectrum for 14 keV P ion impact that shows an internal gain of 3 that has the potential of allowing deterministic implantation of sub-14 keV P ions with reduced straggling.
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Affiliation(s)
- Jessica van Donkelaar
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, Victoria 3010, Australia
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Alves ADC, Newnham J, van Donkelaar JA, Rubanov S, McCallum JC, Jamieson DN. Controlled deterministic implantation by nanostencil lithography at the limit of ion-aperture straggling. NANOTECHNOLOGY 2013; 24:145304. [PMID: 23508018 DOI: 10.1088/0957-4484/24/14/145304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Solid state electronic devices fabricated in silicon employ many ion implantation steps in their fabrication. In nanoscale devices deterministic implants of dopant atoms with high spatial precision will be needed to overcome problems with statistical variations in device characteristics and to open new functionalities based on controlled quantum states of single atoms. However, to deterministically place a dopant atom with the required precision is a significant technological challenge. Here we address this challenge with a strategy based on stepped nanostencil lithography for the construction of arrays of single implanted atoms. We address the limit on spatial precision imposed by ion straggling in the nanostencil-fabricated with the readily available focused ion beam milling technique followed by Pt deposition. Two nanostencils have been fabricated; a 60 nm wide aperture in a 3 μm thick Si cantilever and a 30 nm wide aperture in a 200 nm thick Si3N4 membrane. The 30 nm wide aperture demonstrates the fabricating process for sub-50 nm apertures while the 60 nm aperture was characterized with 500 keV He(+) ion forward scattering to measure the effect of ion straggling in the collimator and deduce a model for its internal structure using the GEANT4 ion transport code. This model is then applied to simulate collimation of a 14 keV P(+) ion beam in a 200 nm thick Si3N4 membrane nanostencil suitable for the implantation of donors in silicon. We simulate collimating apertures with widths in the range of 10-50 nm because we expect the onset of J-coupling in a device with 30 nm donor spacing. We find that straggling in the nanostencil produces mis-located implanted ions with a probability between 0.001 and 0.08 depending on the internal collimator profile and the alignment with the beam direction. This result is favourable for the rapid prototyping of a proof-of-principle device containing multiple deterministically implanted dopants.
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Affiliation(s)
- A D C Alves
- Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Victoria 3010, Australia.
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