Review articleDeterministic doping
Introduction
The second quantum revolution, as described by Dowling [1], is the development of new technologies employing quantum mechanics that has now emerged as a significant field of research. These technologies include quantum computing [2], [3], [4], quantum cryptography [5], quantum simulation [6], [7], quantum metrology [8], [9], quantum sensing in biology [10] or geology [11], quantum time keeping [12], quantum imaging [13] and the quantum internet [14]. There has been significant progress in the development of devices based on the new field of silicon quantum electronics [15] or photonics [16]. In the case of solid state devices employing nuclear or electron spins [17] based on silicon [18] or diamond [19] large scale devices will require the precision engineering of single dopant atoms or colour centres in a crystalline matrix. Ion implantation is already highly developed for silicon in the information technology industry [20] and significant progress has been made towards employing ion implantation to build devices engineered with single atoms in silicon and other materials [21]. For the fabrication of arrays of one or more single atoms the technique of deterministic ion implantation has been developed where implantation is done in conjunction with a method for the registration of each implanted ion.
Recent demonstrations of electron and nuclear spin control of single phosphorus dopant atoms implanted into silicon have shown single donor spin qubits in silicon are strong contenders in the quest for the realization of a scalable quantum computer device [22], [23], [24], [25]. The next step of demonstrating reliable two qubit coupling is likely achievable with existing technology but for this to be achieved on a larger scale requires new techniques for building atomic arrays of implanted donors into silicon including deterministic ion implantation. Also, although much of the present focus is on phosphorus, the heavy donor atoms of arsenic, antimony and bismuth can be implanted into a silicon lattice at a given depth with higher spatial resolution due their higher mass (see Table 1). Also, in the case of arsenic and antimony, diffusion in silicon is less affected by oxidation enhanced diffusion [28] and hence potentially offers higher placement precision compared to phosphorus considering the need for post-implant annealing steps. In the case of antimony the donor electron Bohr orbit diameter is larger than the other donors [26] which may serve to relax constraints on construction precision. Implantation of heavy donor atoms into silicon will cause significant lattice damage, but it has been shown that an ultra-scaled CMOS device can withstand the implantation of erbium isotopes (161<A<171, comparable to bismuth: A=209) where the optically excited charge and spin state of a single implanted erbium atom was detected electrically [29]. Also bismuth donor electron spin resonance can be successfully measured in ensembles implanted into silicon [30]. A potential new application beyond spin qubits in the case of bismuth donors in silicon arises from the fact that the donor electron exhibits technologically useful clock transitions which are insensitive to external perturbations [31]. This transition has so far only been studied in ensembles not in single donors. This demonstrates that ion implantation into wafer scale arrays of fully fabricated and encapsulated devices is a robust method for the introduction of single and few ions and it can be expected that this will also be true for dopant arrays.
Section snippets
Materials and methods
By placing single arsenic, antimony and bismuth atoms in arrays, it is possible, at low temperatures, to configure the local electrostatic landscape of the device for manipulation of the associated donor electrons and through spin-orbit coupling, also the donor nuclear spins. Magnetoelectric transport through single donors is affected by the donor electron level structure, which depends on the dopant-specific properties. Some of these applications employ standard analytical spectroscopic
Silicon
The experimental results from a production run to fabricate counted two or more atom devices with this method is shown in Fig. 3. Here the surface mask contained two 15 nm diameter nanoapertures separated by 50 nm irradiated by a 14 keV P ion beam. The ions can only enter the substrate through the apertures and hence the irradiation continued until two ion implantation signals were recorded above the noise threshold of the on-chip detector electrodes and the associated charge-sensitive electronics.
Conclusion
Ion implanted silicon devices have demonstrated a remarkable range of controlled quantum phenomena, including a recent test of Bell's inequality [78] utilising the electron and nuclear spins of a single implanted 31P atom. Although there are numerous technical challenges to building a large scale device [79], [80], [81] with an array of deterministically implanted atoms, it is probable there will be a convergence of the localisation precision that can be achieved for sub-20 nm range ion
Acknowledgments
This research was supported by the Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology (project number CE110001027) and the US Army Research Office (grant number W911NF-08-1-0527). We acknowledge useful discussions with Thomas Schenkel, Ettore Vittone, Jan Meijer, Daniel Spemann, Kumar Ganesan, Daniel Creedon, Steven Prawer, Andrew Dzurak, Fay Hudson and Andrea Morello. We also acknowledge past members of our group for their contributions to
References (84)
- et al.
SRIM - The Stopping and Range of Ions in Matter (2010)
Nucl. Instr. Methods B
(2010) - et al.
Mapping of ion beam induced current changes in FinFETs
Nucl. Instr. Methods B
(2009) - et al.
Electrical properties and performances of natural diamond nuclear radiation detectors
Nucl. Instr. Methods
(1979) - et al.
Quantum technology: the second quantum revolution
Philos. Trans. R. Soc. Lond. A
(2003) The physical implementation of quantum computation
Fortschr. der Phys. – Prog. Phys.
(2000)A silicon based quantum computer
Nature
(1998)- et al.
Quantum computers
Nature
(2010) - et al.
Quantum cryptography
Rev. Mod. Phys.
(2002) - et al.
Quantum simulations with trapped ions
Nat. Phys.
(2012) - et al.
Photonic quantum simulators
Nat. Phys.
(2012)
Quantum Metrol
Phy. Res. Lab.
Quantum-enhanced measurements: beating the standard Quantum limit
Science
Quantum measurement and orientation tracking of fluorescent nanodiamonds inside living cells
Nat. Nanotechnol.
Electronic properties and metrology applications of the diamond NV− center under pressure
Phys. Rev. Lett.
A quantum network of clocks
Nat. Phys.
Quantum optical metrology - the lowdown on high-N00N states
Contemp. Phys.
Closer to a quantum internet
Phys.
Silicon quantum electronics
Rev. Mod. Phys.
Photonic quantum technologies
Nat. Photonics
Quantum spintronics: engineering and manipulating atom-Like spins in semiconductors
Science
Charge-based quantum computing using single donors in semiconductors
Phys. Rev. B
Creation and nature of optical centres in diamond for single-photon emission – overview and critical remarks
New J. Phys.
Ion implantation in silicon technology
Ind. Phys.
Single atom devices by ion implantation
J. Phys. Cond. Mat.
All electrical nuclear spin polarization of donors in silicon
Phys. Rev. Lett.
High-fidelity readout and control of a nuclear spin qubit in silicon
Nature
A single-atom electron spin qubit in silicon
Nature
Single-shot readout of an electron spin in silicon
Nature
Electric-field driven donor-based charge qubits in semiconductors
Phys. Rev. B
Accurate determination of the intrinsic diffusivities of boron, phosphorus, and arsenic in silicon: the influence of SiO2 film
Jpn. J. Appl. Phys.
Optical addressing of an individual erbium ion in silicon
Nature
Electrical activation and electron spin resonance measurements of implanted bismuth in isotopically enriched silicon-28
Appl. Phys. Lett.
Atomic clock transitions in silicon-based spin qubits
Nat. Nanotechnol.
Excitation spectra of circular, few-electron quantum dots
Science
Broadband electrically detected magnetic resonance of phosphorus donors in a silicon field-effect transistor
Appl. Phys. Lett.
Architecture for high-sensitivity single-shot readout and control of the electron spin of individual donors in silicon
Phys. Rev. B
Charge dynamics of a single donor coupled to a few-electron quantum dot in silicon
Appl. Phys. Lett.
Gate-induced quantum-confinement transition of a single dopant atom in a silicon FinFET
Nat. Phys.
Single donor ionization energies in a nanoscale CMOS channel
Nat. Nanotechnol.
A hybrid double-dot in silicon
New J. Phys.
Electron spin lifetime of a single antimony donor in silicon
Appl. Phys. Lett.
Electrostatically defined silicon quantum dots with counted antimony donor implants
Appl. Phys. Lett.
Cited by (32)
An ion beam spot size monitor based on a nano-machined Si photodiode probed by means of the ion beam induced charge technique
2022, VacuumCitation Excerpt :MeV ion beams are an appealing and versatile tool for the modification, functionalization and analysis of solid state materials [1]. The steady improvements in the last decade in the focusing and collimation of ion beams [2–6] offer enticing opportunities towards the functionalization of materials at the nanoscale [7,8] and the controlled introduction of individual dopants for single-defect engineering by means of ion implantation [9,10]. For processes involving the employment of MeV beams with spot sizes approaching the nanometre scale, the availability of tools for the accurate control on the beam size and resolution is crucial.
Color center formation by deterministic single ion implantation
2021, Semiconductors and SemimetalsCitation Excerpt :Approaches to realize the detection of single ions can be categorized according to the order of detection and implantation, which determines the requirements for the detection efficiency. In post-detection, the ion is detected after it has already been implanted, for example, via the electron-hole pairs that arise from the electronic stopping (IBIC) (Jamieson et al., 2017; Pacheco et al., 2017; van Donkelaar et al., 2015). In contrast, pre-detection is carried out while the ion is still traveling along its trajectory to the target.
Improved Placement Precision of Donor Spin Qubits in Silicon using Molecule Ion Implantation
2024, Advanced Quantum TechnologiesGraphene-Enhanced Single Ion Detectors for Deterministic Near-Surface Dopant Implantation in Diamond
2023, Advanced Functional MaterialsEfficiency Optimization of Ge-V Quantum Emitters in Single-Crystal Diamond upon Ion Implantation and HPHT Annealing
2023, Advanced Quantum Technologies