Eight-qubit operation of a 300 mm SiMOS foundry-fabricated device.

Nickl, Andreas; Dumoulin Stuyck, Nard; Steinacker, Paul; Cifuentes, Jesus D; Serrano, Santiago; Feng, MengKe; Vahapoglu, Ensar; Hudson, Fay E et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Silicon spin qubits are a promising platform for quantum computing due to their high coherence, controllability, and CMOS manufacturability, yet scalable implementations have so far been limited to a few qubits. Here, to take a step towards larger qubit systems, we tune and coherently control an eight-dot linear array of silicon spin qubits fabricated in a 300 mm CMOS-compatible foundry process, establishing operational scalability beyond the two-qubit regime. All eight qubits are successfully tuned and characterized as four double-dot pairs, exhibiting Ramsey dephasing times <math xmlns="http://www.w3.org/1998/Math/MathML"> <msubsup><mrow><mi>T</mi></mrow> <mrow><mn>2</mn></mrow> <mrow><mo>*</mo></mrow> </msubsup> </math> up to 41(2) μs and Hahn-echo coherence times <math xmlns="http://www.w3.org/1998/Math/MathML"> <msubsup><mrow><mi>T</mi></mrow> <mrow><mn>2</mn></mrow> <mrow><mi>Hahn</mi></mrow> </msubsup> </math> up to 1.31(4) ms. Readout of the central four qubits is achieved via a cascaded charge-sensing protocol, enabling high-fidelity measurements of the entire multi-qubit array in a two step process. Additionally, we demonstrate a two-qubit gate operation between adjacent qubits with low phase noise. We show that silicon spin qubit arrays can be scaled to medium-sized arrays of 8 qubits while maintaining system coherence.