Improving mobility of silicon metal-oxide–semiconductor devices for quantum dots by high vacuum activation annealing

¹ CAS Key Laboratory of Quantum Information, University of Science and Technology of China Hefei, Anhui 230026, China
² Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences - Beijing 100029, China
³ Department of Physics and Astronomy, University of California - Los Angeles, CA 90095, USA
⁴ Origin Quantum Computing Company Limited - Hefei, Anhui 230026, China

^(a) haiouli@ustc.edu.cn
^(b) gpguo@ustc.edu.cn

Received: 14 January 2020
Accepted: 22 April 2020

Abstract

To improve mobility of fabricated silicon metal-oxide–semiconductor (MOS) quantum devices, forming gas annealing is a common method used to mitigate the effects of disorder at the Si/SiO₂ interface. However, the importance of activation annealing is usually ignored. Here, we show that a high vacuum environment for implantation activation is beneficial for improving mobility compared to nitrogen atmosphere. Low-temperature transport measurements of Hall bars show that peak mobility can be improved by a factor of two, reaching using high vacuum annealing during implantation activation. Moreover, the charge stability diagram of a single quantum dot is mapped, with no visible disturbance caused by disorder, suggesting the possibility of fabricating high-quality quantum dots on commercial wafers. Our results may provide valuable insights into device optimization in silicon-based quantum computing.