  The attributes of group-V-donor spins implanted in an isotopically purified
$^{28}$Si crystal make them attractive qubits for large-scale quantum computer
devices. Important features include long nuclear and electron spin lifetimes of
$^{31}$P, hyperfine clock transitions in $^{209}$Bi and electrically
controllable $^{123}$Sb nuclear spins. However, architectures for scalable
quantum devices require the ability to fabricate deterministic arrays of
individual donor atoms, placed with sufficient precision to enable
high-fidelity quantum operations. Here we employ on-chip electrodes with
charge-sensitive electronics to demonstrate the implantation of single
low-energy (14 keV) P$^+$ ions with an unprecedented $99.87\pm0.02$%
confidence, while operating close to room-temperature. This permits integration
with an atomic force microscope equipped with a scanning-probe ion aperture to
address the critical issue of directing the implanted ions to precise
locations. These results show that deterministic single-ion implantation can be
a viable pathway for manufacturing large-scale donor arrays for quantum
computation and other applications.
