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Usman M, Bocquel J, Salfi J, Voisin B, Tankasala A, Rahman R, Simmons MY, Rogge S, Hollenberg LCL. Spatial metrology of dopants in silicon with exact lattice site precision. Nat Nanotechnol 2016; 11:763-768. [PMID: 27271965 DOI: 10.1038/nnano.2016.83] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 04/18/2016] [Indexed: 06/06/2023]
Abstract
Scaling of Si-based nanoelectronics has reached the regime where device function is affected not only by the presence of individual dopants, but also by their positions in the crystal. Determination of the precise dopant location is an unsolved problem in applications from channel doping in ultrascaled transistors to quantum information processing. Here, we establish a metrology combining low-temperature scanning tunnelling microscopy (STM) imaging and a comprehensive quantum treatment of the dopant-STM system to pinpoint the exact coordinates of the dopant in the Si crystal. The technique is underpinned by the observation that STM images contain atomic-sized features in ordered patterns that are highly sensitive to the STM tip orbital and the absolute dopant lattice site. The demonstrated ability to determine the locations of P and As dopants to 5 nm depths will provide critical information for the design and optimization of nanoscale devices for classical and quantum computing applications.
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Affiliation(s)
- M Usman
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - J Bocquel
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of New South Wales, Sydney, 2052 New South Wales, Australia
| | - J Salfi
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of New South Wales, Sydney, 2052 New South Wales, Australia
| | - B Voisin
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of New South Wales, Sydney, 2052 New South Wales, Australia
| | - A Tankasala
- Electrical and Computer Engineering Department, Purdue University, West Lafayette, Indiana 47907, USA
| | - R Rahman
- Electrical and Computer Engineering Department, Purdue University, West Lafayette, Indiana 47907, USA
| | - M Y Simmons
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of New South Wales, Sydney, 2052 New South Wales, Australia
| | - S Rogge
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of New South Wales, Sydney, 2052 New South Wales, Australia
| | - L C L Hollenberg
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of Melbourne, Parkville, 3010 Victoria, Australia
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Abstract
The ability to control single dopants in solid-state devices has opened the way towards reliable quantum computation schemes. In this perspective it is essential to understand the impact of interfaces and electric fields, inherent to address coherent electronic manipulation, on the dopants atomic scale properties. This requires both fine energetic and spatial resolution of the energy spectrum and wave-function, respectively. Here we present an experiment fulfilling both conditions: we perform transport on single donors in silicon close to a vacuum interface using a scanning tunneling microscope (STM) in the single electron tunneling regime. The spatial degrees of freedom of the STM tip provide a versatility allowing a unique understanding of electrostatics. We obtain the absolute energy scale from the thermal broadening of the resonant peaks, allowing us to deduce the charging energies of the donors. Finally we use a rate equations model to derive the current in presence of an excited state, highlighting the benefits of the highly tunable vacuum tunnel rates which should be exploited in further experiments. This work provides a general framework to investigate dopant-based systems at the atomic scale.
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Affiliation(s)
- B Voisin
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia
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