Quantum Leap Forward: Silicon Qubits Achieve Scalable Fidelity in Industrial CMOS Fabrication

Imec and Diraq have demonstrated that silicon quantum dot qubits, produced using industrial 300mm complementary metal–oxide–semiconductor (CMOS) processes, achieve error rates suitable for quantum error correction. Published in Nature, the findings show Diraq’s devices, fabricated on Imec’s 300mm spin qubit platform, consistently deliver over 99% fidelity in single- and two-qubit operations, with state preparation and measurement (SPAM) exceeding 99.9%, as verified by gate set tomography (GST). Coherence times and lifetimes reach up to 25 µs.

The qubits, built with a planar metal-oxide-insulator structure and polysilicon gates, utilize a double quantum-dot design on an isotopically enriched 28Si layer to reduce magnetic noise. Randomly selected devices demonstrated reproducible performance, matching the fidelity of academic “hero” devices. The study identifies residual nuclear spin-carrying isotopes as the primary error source, addressable through further isotopic purification, while charge noise from the dielectric environment was not a dominant issue.

Fig: Schematic of a Diraq 2 qubit device on a 300mm wafer

Andrew Dzurak, Diraq’s CEO, stated that leveraging mature semiconductor processes enables cost-effectiv...