The goal of this project is to develop cryo-CMOS circuits for Si-based quantum computers and also to fabricate high-quality Si-based quantum devices. The project consists of three sub-projects. The first one is to design cryo-CMOS circuits which can output RF signals with specified frequency and power that can be applied to drive spin qubit rotation in the Bloch sphere. The second one is to establish cryogenic transistor models that can be employed in the design of the above cryo-CMOS circuits. The last one is to fabricate high-quality Si-based quantum dots which can be operated with high-stability at ultra-low temperatures down to tens of mK. This project is expected to provide the foundations not only for realizing Si-based spin qubits but also for playing a pivotal role in future quantum industries when cryo-CMOS circuits start to replace conventional instruments and take over the control of quantum computers.