Scalable Atomic Arrays for Spin-Based Quantum Computers in Silicon

TL;DR

This paper presents scalable methods for fabricating donor-based silicon quantum computers, including precise implantation and array formation of donor atoms and qudits, advancing the manufacturing of quantum devices.

Contribution

It introduces new implantation techniques and array fabrication methods that enable scalable, high-confidence placement of donor atoms and qudits in silicon for quantum computing.

Findings

Achieved 99.99% confidence in detecting implanted donors.

Demonstrated deterministic formation of regular donor arrays with 300 nm spacing.

Enabled formation of high-dimensional qudits using heavier atoms.

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 we demonstrate and integrate multiple strategies to manufacture scale-up donor-based quantum computers. We use $^{31}$PF$_{2}$ molecule implants to triple the placement certainty compared to $^{31}$P ions, while attaining 99.99$\,$% confidence in detecting the implant. Similar confidence is retained by implanting heavier atoms such as $^{123}$Sb and $^{209}$Bi, which represent high-dimensional qudits for quantum information processing, while Sb$_2$ molecules enable deterministic formation of closely-spaced qudits. We demonstrate the deterministic formation of regular arrays of donor atoms with 300$\,$nm spacing, 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.