# A CMOS dynamic random access architecture for radio-frequency readout of quantum devices

## Abstract

As quantum processors become more complex, they will require efficient interfaces to deliver signals for control and readout while keeping the number of inputs manageable. Complementary metal–oxide–semiconductor (CMOS) electronics offers established solutions to signal routing and dynamic access, and the use of a CMOS platform for the qubits themselves offers the attractive proposition of integrating classical and quantum devices on-chip. Here, we report a CMOS dynamic random access architecture for readout of multiple quantum devices operating at millikelvin temperatures. Our circuit is divided into cells, each containing a control field-effect transistor and a quantum dot device, formed in the channel of a nanowire transistor. This set-up allows selective readout of the quantum dot and charge storage on the quantum dot gate, similar to one-transistor–one-capacitor (1T-1C) dynamic random access technology. We demonstrate dynamic readout of two cells by interfacing them with a single radio-frequency resonator. Our approach provides a path to reduce the number of input lines per qubit and allow large-scale device arrays to be addressed.

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## Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

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## Acknowledgements

The authors thank S. Pauka, S. A. Lyon and M. Schormans for helpful discussions. This research received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 688539 (http://mos-quito.eu) and the Seventh Framework Programme (FP7/2007-2013) through grant agreement no. 318397, as well as from the Engineering and Physical Sciences Research Council (EPSRC) through the Centre for Doctoral Training in Delivering Quantum Technologies (EP/L015242/1) and UNDEDD (EP/K025945/1). M.F.G.Z. and A.R. acknowledge support from the Winton Programme for the Physics of Sustainability and Hughes Hall, University of Cambridge.

## Author information

S.S. and M.F.G.-Z. devised the experiment. S.S., A.R. and M.F.G.-Z. performed the experiments. S.B. fabricated the sample. V.N.C.-T. and T.-Y.Y. performed measurements for low-temperature modelling. V.N.C.-T. developed and performed simulations towards integration. S.S. carried out the analysis and prepared the manuscript, with contributions from A.R., J.J.L.M. and M.F.G.-Z.

Correspondence to Simon Schaal or M. Fernando Gonzalez-Zalba.

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### Competing interests

The authors declare no competing interests.

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## Supplementary information

### Supplementary Information

Supplementary Figs. 1–3, Supplementary Tables 1–2 and Supplementary equations (1)–(6).

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Schaal, S., Rossi, A., Ciriano-Tejel, V.N. et al. A CMOS dynamic random access architecture for radio-frequency readout of quantum devices. Nat Electron 2, 236–242 (2019) doi:10.1038/s41928-019-0259-5

• #### DOI

https://doi.org/10.1038/s41928-019-0259-5

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