Scalable Atomic Arrays for Spin‐Based Quantum Computers in Silicon

Abstract

Semiconductor spin qubits combine excellent quantum performance with the prospect of manufacturing quantum devices using industry‐standard metal‐oxide‐semiconductor (MOS) processes. This applies also to ion‐implanted donor spins, which further afford exceptional coherence times and large Hilbert space dimension in their nuclear spin. Here multiple strategies are demonstrated and integrated to manufacture scale‐up donor‐based quantum computers. 31PF2 molecule implants are used to triple the placement certainty compared to 31P ions, while attaining 99.99% confidence in detecting the implant. Similar confidence is retained by implanting heavier atoms such as 123Sb and 209Bi, which represent high‐dimensional qudits for quantum information processing, while Sb2 molecules enable deterministic formation of closely‐spaced qudits. The deterministic formation of regular arrays of donor atoms with 300 nm spacing is demonstrated, using step‐and‐repeat implantation through a nano aperture. These methods cover the full gamut of technological requirements for the construction of donor‐based quantum computers in silicon.