Millikelvin CMOS-technology for quantum electronics

Scaling up silicon-based quantum processors will require high-performance cryo-CMOS electronics operating at deep cryogenic temperatures. In order to match the power consumption of silicon CMOS integrated circuits to the thermal budget provided by millikelvin refrigeration techniques, Si-MOSFET switching metrics have to be improved beyond current low-temperature limits, set by band-tail states. Based on recent progress in understanding low-temperature band-edge physics in silicon, we introduce fully depleted silicon-on-insulator MOSFETs, manufactured on a cryo-CMOS and SiMOS-qubit pilot line, which are tailored for ultra-low power applications in quantum electronics. With these transistors we consistently achieve record-low subthreshold swing in the range of 0.3 - 2 mV/dec at 0.4 K, enabling a reduction in supply voltage and consequent power dissipation of cryo-CMOS ICs to millikelvin-compatible levels. In combination with back-end processing and packaging techniques designed for cryogenic applications, this can enable very-large-scale integrated quantum ICs for fault-tolerant quantum computing.