Qubits made by advanced semiconductor manufacturing

TL;DR

This paper demonstrates the fabrication of silicon quantum dots using industrial semiconductor manufacturing techniques, achieving high uniformity and qubit quality comparable to traditional methods, thus advancing scalable quantum computing.

Contribution

It introduces a fully industrial process for creating silicon quantum dots with high uniformity and qubit performance, suitable for large-scale quantum computers.

Findings

Quantum dots fabricated in a 300 mm fab with optical lithography.

Achieved relaxation times over 1 second and coherence times over 3 milliseconds.

Demonstrated uniformity and control suitable for fault-tolerant quantum gates.

Abstract

Full-scale quantum computers require the integration of millions of quantum bits. The promise of leveraging industrial semiconductor manufacturing to meet this requirement has fueled the pursuit of quantum computing in silicon quantum dots. However, to date, their fabrication has relied on electron-beam lithography and, with few exceptions, on academic style lift-off processes. Although these fabrication techniques offer process flexibility, they suffer from low yield and poor uniformity. An important question is whether the processing conditions developed in the manufacturing fab environment to enable high yield, throughput, and uniformity of transistors are suitable for quantum dot arrays and do not compromise the delicate qubit properties. Here, we demonstrate quantum dots hosted at a 28Si/28SiO2 interface, fabricated in a 300 mm semiconductor manufacturing facility using all-optical lithography and fully industrial processing. As a result, we achieve nanoscale gate patterns with remarkable homogeneity. The quantum dots are well-behaved in the multi-electron regime, with excellent tunnel barrier control, a crucial feature for fault-tolerant two-qubit gates. Single-spin qubit operation using magnetic resonance reveals relaxation times of over 1 s at 1 Tesla and coherence times of over 3 ms, matching the quality of silicon spin qubits reported to date. The feasibility of high-quality qubits made with fully-industrial techniques strongly enhances the prospects of a large-scale quantum computer