CMOS-based cryogenic control of silicon quantum circuits

• Published in: Nature (London) Vol. 593; no. 7858; pp. 205 - 210
• Main Authors: Xue, Xiao, Patra, Bishnu, van Dijk, Jeroen P. G., Samkharadze, Nodar, Subramanian, Sushil, Corna, Andrea, Paquelet Wuetz, Brian, Jeon, Charles, Sheikh, Farhana, Juarez-Hernandez, Esdras, Esparza, Brando Perez, Rampurawala, Huzaifa, Carlton, Brent, Ravikumar, Surej, Nieva, Carlos, Kim, Sungwon, Lee, Hyung-Jin, Sammak, Amir, Scappucci, Giordano, Veldhorst, Menno, Sebastiano, Fabio, Babaie, Masoud, Pellerano, Stefano, Charbon, Edoardo, Vandersypen, Lieven M. K.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.05.2021; Nature Publishing Group
• Subjects: 639/166/987; 639/766/483/2802; Accuracy; Algorithms; Circuits; CMOS; Complementary metal oxide semiconductors; Control equipment; Cooling; Cryogenic temperature; Design and construction; Dilution; Electron spin; Electronics; Fabrication; Humanities and Social Sciences; Magnetic fields; Metal oxide semiconductors; Microprocessors; multidisciplinary; Quantum computers; Quantum computing; Quantum dots; Qubits (quantum computing); Room temperature; Science; Science (multidisciplinary); Semiconductors; Silicon; Single electrons; Wiring; Netherlands
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-021-03469-4

The most promising quantum algorithms require quantum processors that host millions of quantum bits when targeting practical applications 1 . A key challenge towards large-scale quantum computation is the interconnect complexity. In current solid-state qubit implementations, an important interconnect bottleneck appears between the quantum chip in a dilution refrigerator and the room-temperature electronics. Advanced lithography supports the fabrication of both control electronics and qubits in silicon using technology compatible with complementary metal oxide semiconductors (CMOS) 2 . When the electronics are designed to operate at cryogenic temperatures, they can ultimately be integrated with the qubits on the same die or package, overcoming the ‘wiring bottleneck’ 3 – 6 . Here we report a cryogenic CMOS control chip operating at 3 kelvin, which outputs tailored microwave bursts to drive silicon quantum bits cooled to 20 millikelvin. We first benchmark the control chip and find an electrical performance consistent with qubit operations of 99.99 per cent fidelity, assuming ideal qubits. Next, we use it to coherently control actual qubits encoded in the spin of single electrons confined in silicon quantum dots 7 – 9 and find that the cryogenic control chip achieves the same fidelity as commercial instruments at room temperature. Furthermore, we demonstrate the capabilities of the control chip by programming a number of benchmarking protocols, as well as the Deutsch–Josza algorithm 10 , on a two-qubit quantum processor. These results open up the way towards a fully integrated, scalable silicon-based quantum computer. A cryogenic CMOS control chip operating at 3 K is used to demonstrate coherent control and simple algorithms on silicon qubits operating at 20 mK.