Industry-compatible silicon spin-qubit unit cells exceeding 99% fidelity.

Area of Science:

• Quantum computing
• Semiconductor manufacturing
• Quantum information science

Background:

• Silicon spin qubits are promising for quantum computing due to scalability.
• Previous high-fidelity results were primarily from academic settings.
• Reproducibility in industrial semiconductor foundries remained a key question.

Purpose of the Study:

• To demonstrate precise qubit operation of silicon two-qubit devices manufactured in a 300-mm foundry.
• To assess key performance metrics including fidelity and coherence times.
• To identify factors limiting performance and suggest pathways for improvement.

Main Methods:

• Fabrication of silicon two-qubit devices using standard semiconductor tooling.
• Characterization of qubit performance using gate set tomography.
• Measurement of spin lifetime and coherence times (T1, T2*, T2 Hahn).

Main Results:

• Single- and two-qubit control fidelities exceeded 99% across all devices.
• State preparation and measurement fidelities reached up to 99.9%.
• Reported coherence times up to T1 = 9.5 s, T2* = 40.6 μs, and T2 Hahn = 1.9 ms.

Conclusions:

• Foundry-scale manufacturing of silicon spin qubits is feasible with high performance.
• Residual nuclear isotopes significantly impact operational errors.
• Further isotopic purification offers a clear route to enhance qubit performance.