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Fabrication of Isotopically Enriched, Industry-Compatible Wafers Points Way To Realizing Silicon Spin Quantum Bits with Enhanced Fidelity
GRENOBLE, France – March 20, 2018 – CEA-Leti, a French technology research institute of the CEA and Inac, a joint fundamental research institute between the CEA and the University Grenoble Alpes, today announced a breakthrough towards large-scale fabrication of quantum bits, or qubits, the elementary bricks of future quantum processors. They demonstrated on a 300 mm pre-industrial platform a new level of isotopic purification in a film deposited by chemical vapor deposition (CVD). This enables creating qubits in thin layers of silicon using a very high purity silicon isotope, 28Si, which produces a crystalline quality comparable to thin films usually made of natural silicon.
“Using the isotope 28Si instead of natural silicon is crucial for the optimization of the fidelity of the silicon spin qubit,” said Marc Sanquer, a research director at Inac. “The fidelity of the spin qubit is limited to small values by the presence of nuclear spins in natural silicon. But spin qubit fidelity is greatly enhanced by using 28Si, which has zero nuclear spin. We expect to confirm this with qubits fabricated in a pre-industrial CMOS platform at CEA-Leti.”
“To progress towards a practical and useful quantum processor, it is now essential to scale up the qubit,” said Louis Hutin, a research engineer in CEA-Leti’s Silicon Components Division. “This development will have to address variability, reproducibility and electrostatic control quality for elementary quantum bricks, as is done routinely for standard microprocessors.”
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.