For semiconductor spin qubits, complementary-metal-oxide-semiconductor (CMOS) technology is a promising candidate for reliable and scalable fabrication. Making the direct leap from academic fabrication to qubits fully fabricated by industrial CMOS standards is difficult without intermediate solutions. With a flexible back-end-of-line (BEOL), functionalities such as micromagnets or superconducting circuits can be added in a post-CMOS process to study the physics of these devices or achieve proofs-of-concept. Once the process is established, it can be incorporated in the foundry-compatible process flow. Here, we study a single electron spin qubit in a CMOS device with a micromagnet integrated in the flexible BEOL. We exploit the synthetic spin orbit coupling (SOC) to control the qubit via electric fields and we investigate the spin-valley physics in the presence of SOC where we show an enhancement of the Rabi frequency at the spin-valley hotspot. Finally, we probe the high frequency noise in the system using dynamical decoupling pulse sequences and demonstrate that charge noise dominates the qubit decoherence in this range.

对于半导体自旋量子位，互补金属氧化物半导体 (CMOS) 技术是实现可靠且可扩展制造的有希望的候选技术。如果没有中间解决方案，从学术制造直接跨越到完全按照工业 CMOS 标准制造的量子位是很困难的。借助灵活的后端 (BEOL)，可以在后 CMOS 工艺中添加微磁体或超导电路等功能，以研究这些设备的物理原理或实现概念验证。一旦建立了工艺，就可以将其合并到与铸造厂兼容的工艺流程中。在这里，我们研究了 CMOS 器件中的单电子自旋量子位，该器件在柔性 BEOL 中集成了微磁体。我们利用合成自旋轨道耦合 (SOC) 通过电场控制量子位，并研究了 SOC 存在下的自旋谷物理现象，其中显示了自旋谷热点处拉比频率的增强。最后，我们使用动态去耦脉冲序列探测系统中的高频噪声，并证明电荷噪声在该范围内主导量子位退相干。