Cryogenic CMOS (cryo-CMOS) is a viable technology for the control interface of the large-scale quantum computers able to address non-trivial problems. In this paper, we demonstrate state-of-the-art cryo-CMOS circuits and systems for such application and we discuss the challenges still to be faced on the path towards practical quantum computers.

This work presents an experimental study of different components (resistors, diodes, transistors) in a standard 40-nm bulk CMOS process for their suitability as integrated cryogenic temperature sensors down to a temperature of 4.2 K. It was found that most devices can be employed as sensors down to temperatures of approximately 50 K, below which non-ideal effects such as non-linear behaviour and decreased sensitivity start to dominate. The Dynamic-Threshold MOS (DTMOS) was found to be a very promising candidate for its linearity, low forwardvoltage-drop and sensitivity down to 8 K. Moreover, as previous research indicated that cryogenic self-heating raises the local chip temperature to tens of Kelvins already at moderate power levels, the aforementioned sensing limitations at very low temperatures are expected to be of less importance in realistic applications. The results presented in this work contribute to the further integration of classical cryo-CMOS control electronics and qubits, towards a fully scalable quantum computer.

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