Silicon spin qubits are a promising platform for realizing large-scale quantum processors, owing to their compatibility with advanced semiconductor integration technologies. However, one of the major challenges lies in the complexity of qubit control, which typically requires a large number of accurate analog signals delivered through extensive wiring from room temperature to cryogenic environments. Such wiring not only introduces signal interference but also increases the thermal load on the dilution refrigerator, thereby limiting the overall fidelity and scalability of the qubit system. To address these challenges, this work explores circuit-level solutions through the development of cryo-CMOS analog control electronics integrated inside the refrigerator. This approach reduces the need for external wiring and enhances signal integrity at cryogenic temperatures.
This talk introduces two key cryo-CMOS analog circuit implementations developed for silicon spin qubit control. The first is a cryogenic DAC operating at 4 K, designed to apply precise gate bias voltages to the qubits. The DAC employs an architecture that effectively leverages transistor characteristics at cryogenic temperature to achieve compact size and low power consumption, enabling multi-channel gate bias generation under the strict power and area constraints of the refrigerator. The second is a cryogenic ADC operating at deep cryogenic temperature of 100 mK, which enables high-resolution acquisition of gate-pulse waveforms near the qubit. This cryogenic ADC achieves both ultra-low power consumption and wide input bandwidth, making it suitable for in-situ signal monitoring at the quantum-classical interface.