Quobly, a leading French quantum computing startup, has reported that FD-SOI technology can serve as a scalable platform for commercial quantum computing, leveraging traditional semiconductor manufacturing fabs and CEA-Leti's R&D pilot line.

The semiconductor industry has played a pivotal role in enabling classical computers to scale at cost; it has the same transformative potential for quantum computers, making them commercially scalable and cost competitive. Silicon spin qubits are excellent for achieving fault-tolerant, large-scale quantum computing, registering clock speeds in the µsec range, fidelity above 99% for one and two-qubit gate operations and incomparably small unit cell sizes (in the hundredths of 100 nm²).To capitalize on decades of semiconductor infrastructure investments, Quobly has adopted a fabless model. It focuses on FD-SOI, a commercially available CMOS technology manufactured by global leaders like STMicroelectronics, GlobalFoundries, and Samsung, as a platform for quantum computing.

Quobly's work, reported on December 9th, 2024 at IEDM, addresses the critical challenges for scaling quantum systems. With CEA-Leti, CEA-IRIG and CNRS, Quobly has demonstrated the key building blocks for a quantum computer leveraging commercial FD-SOI:

Low-temperature operations and characterization of their digital and analog performances, adhering to circuit design guidelines
Single qubit operations using hole and electron spin qubits using the CEA-Leti's R&D pilot line. This ambipolar platform optimizes system performance, leveraging electrons' long coherence times for memory, as well as the holes' strong spin-orbit interaction for fast data processing
Charge control in commercial GF 22FDX to further define a standard cell for a two-qubit gate

Key achievements include:

• Cryogenic Control Electronics: Voltage gain up to 75dB, noise levels of 10-11 V²∙μm²/Hz, and threshold voltage variability of 1.29 mV∙μm.
• Ambipolar Spin Qubits: Co-integration of hole and electron qubits on FD-SOI technology, achieving 1μs manipulation speed for holes and 40μs coherence time (Hahn echo) for electrons.
• Two-Qubit Gate Standard Cell: Demonstration of double quantum dot operations with commercial FD-SOI.A Step Towards Commercial Quantum Systems

This work positions FD-SOI as essential for scalable quantum processors and establishes Quobly as a leader in cost-efficient, fault-tolerant quantum computing. By co-integrating quantum and classical components on the same platform, Quobly is shaping scalable QSoC architectures.