A Wide Temperature Range Voltage Reference for Quantum Computing Applications

Quantum computers seem very promising in solving problems that are too large to be solved by classical computers that are available today. However, to generate reasonable amounts of computing power, many qubits will be required. Each of the qubits has to be individually controlled and needs to be kept at cryogenic temperatures. To allow for the scaling of the number of qubits, control electronics are being developed, that operate close to the qubits, at a temperature of 4 Kelvin. These control electronics require a voltage reference as well. In this thesis, several voltage references implemented in a commercial 40-nm CMOS process will be presented. The voltage references are designed for the temperature range from 4.2 K up to 400 K. As bipolar transistors are not suited for operation at cryogenic temperatures, the references are implemented using MOS devices. Architectures employing NMOS, PMOS and DTMOS as core device have been implemented

Cryo-CMOS for Analog/Mixed-Signal Circuits and Systems

CMOS circuits operating at cryogenic temperature (cryo-CMOS) are required in several low-temperature applications. A compelling example is the electronic interface for quantum processors, which must reside very close to the cryogenic quantum devices it serves, and hence operate at the same temperature, so as to enable practical large-scale quantum computers. Such cryo-CMOS circuits must achieve extremely high performance while dissipating minimum power to be compatible with existing cryogenic refrigerators. These requirements asks for cryo-CMOS electronics on par with or even exceeding their room temperature counterparts. This paper overviews the challenges and the opportunities in designing cryo-CMOS circuits, with a focus on analog and mixed-signal circuits, such as voltage references and data converters