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

Schenkel, T.; Liddle, J. Alexander; Persaud, A.; Tyryshkin, Alexei M.; Lyon, S. A.; Sousa, Rogério de; Whaley, K. Birgitta; Bokor, Jeffrey; Shangkuan, J.; Chakarov, I.

doi:10.1063/1.2182068

Cited by 84 publications

(91 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Electron spin relaxation times of implanted donors, T 1e , at 5 K are ~15 ms [2], and nuclear spin relaxation times, T 1n are at least 300 times longer [15]. But T 1e and T 1n during EDMR measurements are not yet known.…”

mentioning

confidence: 99%

“…Moreover, electron spin relaxation rates of implanted 121 Sb and the Stark effect due to applied electric fields have been previously studied in detail [2,3]. In the limit of a single-donor doped aFET, an EDMR experiment can yield spectra where information on a single nuclear spin state can be deduced from the presence (and absence) of donor hyperfine-split peaks, provided that the read-out time is faster than the spin-flip time of the nuclear spin.…”

mentioning

confidence: 99%

“…Donor atoms (e. g. phosphorus [1] or antimony [2,3]) embedded in a silicon substrate are the basis for quantum bits (qubits), and spins of donor electrons and nuclei are utilized for quantum information storage and manipulation. An integral part of any quantum computation architecture is a high-fidelity qubit readout.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Spin-dependent scattering off neutral antimony donors in Si28 field-effect transistors

Bokor

Schenkel

et al. 2007

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

We report measurements of spin-dependent scattering of conduction electrons by neutral donors in accumulation-mode field-effect transistors formed in isotopically enriched silicon. Spin-dependent scattering was detected using electrically detected magnetic resonance where spectra show resonant changes in the source-drain voltage for conduction electrons and electrons bound to donors. We discuss the utilization of spindependent scattering for the readout of donor spin-states in silicon based quantum computers. Neutral impurity scattering is spin-dependent because different spin configurations of the conduction and donor electrons (singlet or triplet) imply a different spatial distribution of the two-electron wavefunction, which translates into a difference in scattering crosssections. This SDS process by phosphorus impurities in an accumulation-mode fieldeffect transistor (aFET) was first observed by Ghosh and Silsbee using electrically detected magnetic resonance (EDMR) [9]. In an EDMR experiment, a static magnetic field induces a Zeeman splitting in the electron energy levels, and in thermal equilibrium, triplet scattering is favored as more spins are aligned with the static field. Singlet scattering can be enhanced by inducing spin flips with a resonant microwave field. This increase in singlet content then registers as an effective channel resistance change of the 3 aFET. Ghosh and Silsbee used large-area aFETs (1×0.1 mm 2 ) formed in bulk-doped silicon with about 2×10 17 phosphorus/cm 3 [9]. The number of donors close (~10 nm) to the aFET channel that contribute to SDS was estimated to be ~10 8 . However, bulk donors far away from the channel that did not contribute to SDS caused an undesired bolometric signal due to resonant microwave absorption, and substantial efforts were undertaken to resolve interfering bolometric effects and to isolate the SDS signal.In the present work, we demonstrate SDS by neutral 121 Sb donors in silicon aFETs. In order to avoid bolometric signals, aFETs were formed in undoped silicon and ~6×10 6 donors were implanted into the transistor channel. While most donor-based silicon quantum computer proposals have suggested spins of 31 P as qubits, 121 Sb is used in our experiments due to its smaller straggling in the channel implantation process, lower diffusion rates in silicon, and to avoid spurious signals arising from residual background 31 P atoms in the silicon substrate or from the polycrystalline silicon gate.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Spin-dependent scattering off neutral antimony donors in Si28 field-effect transistors

Bokor

Schenkel

et al. 2007

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…This theoretical explanation opens the way to novel microscopic interpretations of a series of pulse electron spin resonance experiments, where the electron spin may be viewed as a spectrometer of low frequency magnetic noise due to a large number of nuclear spins or other magnetic moments. For example, a recent experiment [37] revealed that magnetic noise from the surface must play a role on spin echo decay of antimony impurities implanted in isotopically purified silicon (with a very low density of 29 Si nuclear spins in the bulk).…”

Section: Conclusion and Outlook For The Futurementioning

confidence: 99%

Electron Spin as a Spectrometer of Nuclear-Spin Noise and Other Fluctuations

Sousa

2009

Topics in Applied Physics

View full text Add to dashboard Cite

“…Isotope engineered substrates provide a nuclear spin free host environment, resulting in long electron and nuclear spin coherence times of several seconds [3,4]. Spin properties of donor qubit candidates in silicon have been studied mostly for phosphorous and antimony [3][4][5][6]. Bismuth donors in silicon are unique in exhibiting a relatively large zero field splitting of 7.4 GHz.…”

mentioning

confidence: 99%

Electrical activation and electron spin resonance measurements of implanted bismuth in isotopically enriched silicon-28

Weis

Lang

et al. 2012

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

We have performed continuous wave and pulsed electron spin resonance measurements of implanted bismuth donors in isotopically enriched silicon-28. Donors are electrically activated via thermal annealing with minimal diffusion. Damage from bismuth ion implantation is repaired during thermal annealing as evidenced by narrow spin resonance linewidths (Bpp = 12 µT) and long spin coherence times (T2 = 0.7 ms, at temperature T = 8 K). The results qualify ion implanted bismuth as a promising candidate for spin qubit integration in silicon.Electron and nuclear spins of donor atoms in silicon are excellent qubit candidates for quantum information processing [1, 2]. Isotope engineered substrates provide a nuclear spin free host environment, resulting in long electron and nuclear spin coherence times of several seconds [3,4]. Spin properties of donor qubit candidates in silicon have been studied mostly for phosphorous and antimony [3][4][5][6]. Bismuth donors in silicon are unique in exhibiting a relatively large zero field splitting of 7.4 GHz. Thus, they have attracted attention as potential nuclear spin memory and spin qubit candidates [7,8] that could be coupled to superconducting resonators [7,9,10]. Bismuth is the deepest donor in silicon with a binding energy of 70 meV and a corresponding small Bohr radius. The small Bohr radius and bismuth's reduced effective gyromagnetic ratio [7] can make it less susceptible to interface noise at a given implant depth and make bismuth very desirable for quantum logic implementation via magnetic dipolar coupling [11]. Furthermore, bismuth is also the heaviest donor in silicon and thus shows the least ion range straggling during ion implantation, which enables for donor qubit placement with high spatial resolution [12,13].To date, studies of spin resonance properties of bismuth in silicon have been performed with bulk doped natural silicon [7,8,[14][15][16] whereas silicon-28 material is preferable for improved spin coherence properties. Electrical activation of implanted bismuth via thermal anneals has been studied for relatively high implant doses [17][18][19][20][21], and concentrations close to the the metalinsulator transition (N c = 1.7 × 10 19 cm −3 ) [18]. High implant doses ( 1 × 10 14 cm −2 for keV Bi-ions at room temperature) amorphize the silicon lattice [22]. Solid- * Please contact the corresponding author under cdweis@lbl.gov phase epitaxial regrowth (SPER) can be used to prevent diffusion of bismuth atoms and incorporate them on substitutional sites. This can lead to electrically active concentrations well above the low relatively solubility limit of bismuth in silicon (which is, e.g. 2.3 × 10 17 cm −3 at 1150 ℃ [23]). For SPER, thermal anneals at low temperatures, e.g. few minutes at 600 ℃ yield electrical activation levels of up to 90 % [20]. For low implant doses and dopant concentrations, which are desirable for long spin coherence times, no amorphization of the silicon crystal occurs during ion implantation. Thus, the electrical activation levels and annealing ...

show abstract

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

Cited by 84 publications

References 21 publications

Spin-dependent scattering off neutral antimony donors in Si28 field-effect transistors

Spin-dependent scattering off neutral antimony donors in Si28 field-effect transistors

Electron Spin as a Spectrometer of Nuclear-Spin Noise and Other Fluctuations

Electrical activation and electron spin resonance measurements of implanted bismuth in isotopically enriched silicon-28

Contact Info

Product

Resources

About