Characterization of SOS-CMOS FETs at Low Temperatures for the Design of Integrated Circuits for Quantum Bit Control and Readout

We have assessed the use of commercial silicon-on-sapphire CMOS electronics in control circuits, which could be used to interface with quantum bits at low temperatures. We have characterized n-type MOSFETs, p-type MOSFETs, and an n⁺-diffusion resistor at 300 K and 4.2 K and extended these studies into the millikelvin regime. Our measurements of dc responses at 300 K, 4.2 K, and subkelvin and transient responses at 300 K and 4.2 K show that these devices favorably operate at low temperatures with minor changes to their 300-K characteristics and no appreciable change to their operating speed. Our results indicate that control circuits based on commercial CMOS devices may successfully be operated at low temperatures for the control and readout of quantum bits.