Eight-Qubit Operation of a 300 mm SiMOS Foundry-Fabricated Device

Silicon spin qubits are a promising candidate for quantum computing, thanks to their high coherence, high controllability and manufacturability. However, the most scalable complementary metal-oxide-semiconductor (CMOS) based implementations have so far been limited to a few qubits. Here, to take a step towards large scale systems, we tune and coherently control an eight-dot linear array of silicon spin qubits fabricated in 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 $T_2^*$ up to 41(2) $\mu$s and Hahn-echo coherence times $T_2^{\mathrm{Hahn}}$ up to 1.31(4) ms. Readout of the central four qubits is achieved via a cascaded charge-sensing protocol, enabling simultaneous high-fidelity measurements of the entire multi-qubit array. Additionally, we demonstrate a two-qubit gate operation between adjacent qubits with low phase noise. We demonstrate here that we can scale silicon spin qubit arrays to medium-sized arrays of 8 qubits while maintaining coherence of the system.