Quantum computing exploits fundamental principles of quantum mechanics, such as superposition and entanglement, to tackle problems in mathematics, chemistry, and material science. Its power is derived from a quantum bit (qubit) that can exist in a superposition state and can become entangled with other qubits. It has been shown that quantum computers can display a speed up compared to some classic algorithms and, potentially, model any physical process. The prospects of quantum computing have triggered extensive worldwide research in both industry and academia: quantum computing is now the main driver behind the phenomenal development of cryogenic CMOS, or cryo-CMOS, a process allowing one to create integrated microchips operating at ultra low temperatures of few kelvins and below. Semiconductor CMOS qubits, quantum gates and few-qubit semiconductor quantum processors have been successfully demonstrated in practice over recent years. This shows a prospect of the massive integration of nanometer-size CMOS qubits. For electronic engineers, the “holy grail” in quantum computing is to integrate the quantum processor and control electronics on a single silicon die— a “quantum computer on a chip” that will be scalable and inexpensive.