Silicon Carbide Qubits towards a Fab-Ready Technology

• Applicant: Dr.-Ing. Julietta Miriam Förthner
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 532769051

Spin qubits associated to optically active solid-state defects are being explored as a platform for quantum networks. Recently, the silicon vacancy centre (VSi) in silicon carbide (SiC) was identified as a promising candidate for future scalability. Compared to currently leading platforms, such as the NV centre in diamond, the VSi offers improved potential for nano-photonic device integration and high operation temperatures (up to T=20 K). Additionally, SiC is an industrially mature semiconductor that has the potential for scalable integrated device fabrication. Initial experiments with the VSi centre by our consortium and others have demonstrated quantum control over electron- and nuclear-spin qubits, spin-controlled photon emission, and excellent spin and optical coherences even after nanophotonic integration. These experiments provide a promising starting point towards a future SiC quantum technology. Key open challenges are to develop device fabrication methods that are “fab-ready”, in the sense of transferring established CMOS fabrication to quantum device manufacturing or developing new processes that are compatible to clean room operation (i.e., scalable, reliable and without contamination issues). Today, it is unclear whether such processes can be made “quantum-grade”, i.e., permit high-fidelity multi-qubit control and photon-mediated entanglement. SiCqurTech will investigate material growth and fabrication processes to lay the foundation for such a fab-ready technology, and will explore its potential for quantum networks. To this end, we bring together an interdisciplinary European consortium that will: (1) explore the growth of novel quantum-grade SiC with controlled isotopic concentrations; (2) develop fab-compatible SiC-on-insulator technology and electrical control structures via high-throughput characterisation; (3) investigate charge passivating SiC surfaces with low-background fluorescence; (4) demonstrate multi-qubit-control (up to 10 qubits) and photon mediated entanglement. SiCqurTech’s results will create a comprehensive fundamental and practical understanding of the potential of the VSi centre in SiC as a scalable next-generation quantum network technology.

• DFG Programme: Research Grants
• International Connection: France, Luxembourg, Netherlands, Sweden, Switzerland
• Partner Organisation: Agence Nationale de la Recherche / The French National Research Agency
• Co-Investigator: Professor Dr.-Ing. Jörg Schulze
• Cooperation Partners: Professorin Dr. Ulrike Grossner; Dr. Florian Kaiser; Dr. Tim Hugo Taminiau; Dr. Jawad Ul-Hassan