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

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 T₂* up to 41(2) μs and Hahn-echo coherence times T₂^Hahn 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. Scaling silicon spin qubit platforms requires coherent control of larger foundry-fabricated arrays. Here, the authors demonstrate tuning, pairwise coherent control, and readout of an eight-qubit linear array in silicon fabricated in a 300 mm CMOS compatible process, with state-of-the-art coherence and low noise two-qubit operation.