Implanted single group-V donor ions in isotopically-enriched silicon (²⁸Si) provide a promising platform for quantum computing due to their long spin coherence times [1]. Both the donor electron and nuclear spins can be used as qubits, which can be coupled via various mechanisms over a range of length scales. Ion implantation provides a flexible method for introducing a variety of species into silicon: molecule ions can boost qubit placement precision [2] and high nuclear spin donors, such as antimony (¹²³Sb), can be used as higher-dimensional qudits or error-corrected qubits.

Large-scale arrays of qubits, such as in the flip-flop qubit architecture for donor spins [3], are required to run useful quantum algorithms. Deterministic ion implantation, in which single ions are implanted into precise locations, is essential for producing these donor qubit arrays. Recent work [4] has demonstrated the formation of arrays of donor spins of various species using a step-and-repeat process in which ions are implanted through a moveable nanostencil into an ion beam induced charge (IBIC) detector with high detection confidence. Molecule ions are being explored for their ability to produce high placement precision ³¹P qubits and closely-spaced coupled ¹²³Sb qudits. The next generation of detectors will enable the integration of qubit control and readout nanocircuitry with deterministically-implanted donor spins, to drive the scale-up of quantum computers. 

[1] J. T. Muhonen et al.,  Nature Nano. 9, 986 (2014)

[2] D. Holmes et al., Advanced Quantum Technologies 7, 2300316 (2024)

[3] G. Tosi et al., Nature Comm. 8, 450 (2017)

[4] A. M. Jakob et al., arXiv preprint arXiv:2309.09626 (2023)