Cryogenic Adiabatic CMOS for Ultra-Low Power Circuits

This project will design analog and digital CMOS circuits for cryogenic operation. Power dissipation is the greatest challenge facing the development of electronic systems today.  Both passive (leakage) power and active (operating) power are growing at unsustainable rates. Cryogenic temperatures offer a number of advantages to CMOS circuits. Foremost is that leakage currents are reduced leading to lower passive dissipation.  Drain to Source leakage current is reduced because the subthreshold swing is improved at low temperatures.  This can enable circuits to operate at lower voltages to reduce the energy needed to encode information.  This project will use adiabatic digital circuits, which recover and recycle the energy used to encode information, and can have an active dissipation that is orders of magnitude below that of conventional circuits. Since energy is required to cool the circuits, active power of the cryogenic circuits is a particular concern.  These digital circuits will include, basic digital test circuits, a 16-bit adiabatic ALU, and an energy-recover static RAM.   In addition to digital test circuits, analog circuits such as an RF generator, transimpedance amplifier, and digital to analog converter.  These are important building blocks for quantum computing and quantum information processing.  These quantum processes require low temperatures to operate, but also require a significant number of analog control signals and analog and digital processing.  In today’s early systems much of these control signals are provided from room temperature sources, and processing is done at room temperature, requiring a very large number of cables going from the room temperature equipment to the cryogenic qubits.  For quantum systems to become practical, much of this circuitry must be move to low temperatures.  This project will be an important step in the development of the needed low-temperature CMOS circuits.