Integration of Scanning Probes and Ion Beams

Persaud, A.; Park, S. J.; Liddle, J. Alexander; Schenkel, T.; Bokor, Jeffrey; Rangelow, Ivo W.

doi:10.1021/nl0506103

Cited by 45 publications

(36 citation statements)

References 30 publications

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“…Formation of test devices for quantum information processing requires the integration of individual dopant atoms with a control and readout infrastructure. Donor array fabrication is being addressed by ion implantation [4][5][6] and scanning probe based hydrogen lithography [7,8]. Dopant spacing depends on the choice of entangling interactions between quantum bits (qubits) and ranges from 20 to over 100 nm, corresponding to ultra low ion implantation doses of <10 10 to 2.5×10 11 cm -2 .…”

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confidence: 99%

Electrical activation and electron spin coherence of ultralow dose antimony implants in silicon

Schenkel

Liddle

Persaud

et al. 2006

Applied Physics Letters

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We implanted ultra low doses (2×10 11 cm -2 ) of 121 Sb ions into isotopically enriched 28 Si and find high degrees of electrical activation and low levels of dopant diffusion after rapid thermal annealing. Pulsed Electron Spin Resonance shows that spin echo decay is sensitive to the dopant depths, and the interface quality. At 5.2 K, a spin decoherence time, T 2 , of 0.3 ms is found for profiles peaking 50 nm below a Si/SiO 2 interface, increasing to 0.75 ms when the surface is passivated with hydrogen. These measurements provide benchmark data for the development of devices in which quantum information is encoded in donor electron spins.* Email: T_Schenkel@LBL.gov 1 cond-mat/0507318Spins of electrons bound to donor atoms in silicon at low temperature are promising candidates for the development of quantum information processing devices [1][2][3]. This is due to their long decoherence times, and the potential to leverage fabrication finesse in a silicon transistor paradigm. Recently, relatively long transverse relaxation times (T 2 ) were determined for electron spins in pulsed electron spin resonance (ESR) studies of phosphorous donors in isotopically enriched silicon. Here, donors were present as a random background doping across 28 Si epi layers and T 2 extrapolated to 60 ms for isolated donors [3]. Formation of test devices for quantum information processing requires the integration of individual dopant atoms with a control and readout infrastructure. Donor array fabrication is being addressed by ion implantation [4][5][6] and scanning probe based hydrogen lithography [7,8]. Dopant spacing depends on the choice of entangling interactions between quantum bits (qubits) and ranges from 20 to over 100 nm, corresponding to ultra low ion implantation doses of <10 10 to 2.5×10 11 cm -2 . In this letter, we report on depth profiles and electrical activation following rapid thermal annealing (RTA) of ultra low dose 121 Sb implants and correlate electron spin relaxation times with the dopant distribution below an interface and with the interface quality.We processed wafers with 10 μm thick, 28 Si enriched epi layers (500 ppm 29 Si) on p-type natural silicon (100) and natural silicon control wafers (100), both with impurity concentrations ≤10 14 cm -3 . Standard CMOS processes were followed for formation of 5-10 nm thick thermal SiO 2 . Typical densities of trapped charges and interface traps were 1 to 2×10 11 cm -2 for the thermal oxides. 121 Sb-ion implantation with a dose of 2×10 11 cm -2 was conducted with implant energies of 120 keV and 400 keV. 121 Sb was used to avoid any ambiguity of results due to 31 P background in 28 Si epi layers. RTA for repair of 2 cond-mat/0507318 implant damage and substitutional incorporation of dopants into the silicon lattice, i. e., electrical activation, was performed with an AGA Heatpulse 610. Following annealing, carrier depth profiles were probed with Spreading Resistance Analysis (SRA) [9]. Secondary Ion Mass Spectrometry (SIMS) [9] was used to characterize elemental depth ...

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confidence: 99%

Electrical activation and electron spin coherence of ultralow dose antimony implants in silicon

Schenkel

Liddle

Persaud

et al. 2006

Applied Physics Letters

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“…In our approach to single atom doping, we integrate broad ion beams from a series of ion sources with a scanning force microscope ͑SFM͒. 7,8 Here, a small ͑Ͻ100 nm͒ hole in the tip of the SFM cantilever acts as an aperture and defines the beam spot. With this technique we have demonstrated formation of arbitrary patterns in resist layers with feature sizes down to 90 nm.…”

Section: Introductionmentioning

confidence: 99%

“…With this technique we have demonstrated formation of arbitrary patterns in resist layers with feature sizes down to 90 nm. [7][8][9][10] Furthermore, we recently demonstrated single atom doping and single atom implantation into transistors with 100% efficiency. 11 We have also addressed a third requirement for single atom device development, namely, the retention of dopant arrays and profiles throughout the entire device fabrication process.…”

Section: Introductionmentioning

confidence: 99%

Single atom doping for quantum device development in diamond and silicon

Weis

Schuh

Batra

et al. 2008

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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The ability to inject dopant atoms with high spatial resolution, flexibility in dopant species, and high single ion detection fidelity opens opportunities for the study of dopant fluctuation effects and the development of devices in which function is based on the manipulation of quantum states in single atoms, such as proposed quantum computers. The authors describe a single atom injector, in which the imaging and alignment capabilities of a scanning force microscope ͑SFM͒ are integrated with ion beams from a series of ion sources and with sensitive detection of current transients induced by incident ions. Ion beams are collimated by a small hole in the SFM tip and current changes induced by single ion impacts in transistor channels enable reliable detection of single ion hits. They discuss resolution limiting factors in ion placement and processing and paths to single atom ͑and color center͒ array formation for systematic testing of quantum computer architectures in silicon and diamond.

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“…The demonstration of efficient electron transport through single, micrometer long, and well aligned carbon nanotubes has the potential to realize new classes of collimators and beam optics for energetic particles -ions [13] as well as electrons. CNT beam transport elements can e. g. enable the placement of dopant atoms with nm precision, beyond current limits in ion beam focusing [13] …”

mentioning

confidence: 99%

“…CNT beam transport elements can e. g. enable the placement of dopant atoms with nm precision, beyond current limits in ion beam focusing [13] …”

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confidence: 99%

Electron transport through single carbon nanotubes

Chai

Heinrich

Chow

et al. 2007

Applied Physics Letters

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The authors report on the transport of energetic electrons through single, well aligned multiwall carbon nanotubes (CNTs). Embedding of CNTs in a protective carbon fiber coating enables the application of focused ion beam based sample preparation techniques for the nondestructive isolation and alignment of individual tubes. Aligned tubes with lengths of 0.7–3μm allow transport of 300keV electrons in a transmission electron microscope through their hollow cores at zero degree incident angles and for a misalignment of up to 1°.

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Integration of Scanning Probes and Ion Beams

Cited by 45 publications

References 30 publications

Electrical activation and electron spin coherence of ultralow dose antimony implants in silicon

Electrical activation and electron spin coherence of ultralow dose antimony implants in silicon

Single atom doping for quantum device development in diamond and silicon

Electron transport through single carbon nanotubes

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