中国物理B ›› 2025, Vol. 34 ›› Issue (9): 90305-090305.doi: 10.1088/1674-1056/add4de

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Impact of surface passivation on the electrical stability of strained germanium devices

Zong-Hu Li(李宗祜)1,2, Mao-Lin Wang(王茂粼)1,2, Zhen-Zhen Kong(孔真真)3,4,5,6, Gui-Lei Wang(王桂磊)3,5,6,‡, Yuan Kang(康原)1,2, Yong-Qiang Xu(徐永强)1,2, Rui Wu(吴睿)1,2, Tian-Yue Hao(郝天岳)1,2, Ze-Cheng Wei(魏泽成)1,2, Bao-Chuan Wang(王保传)1,2, Hai-Ou Li(李海欧)1,2,5, Gang Cao(曹刚)1,2,5,†, and Guo-Ping Guo(郭国平)1,2,5,7   

  1. 1 CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China;
    2 CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China;
    3 Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China;
    4 Institute of Microelectronics, University of Chinese Academy of Sciences, Beijing 100049, China;
    5 Hefei National Laboratory, Hefei 230088, China;
    6 Beijing Superstring Academy of Memory Technology, Beijing 100176, China;
    7 Origin Quantum Computing Company Limited, Hefei 230088, China
  • 收稿日期:2025-02-17 修回日期:2025-04-22 接受日期:2025-05-07 出版日期:2025-08-21 发布日期:2025-09-04
  • 通讯作者: Gang Cao, Gui-Lei Wang E-mail:gcao@ustc.edu.cn;guilei.wang@bjsamt.org.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 92265113, 12034018, 12474490, and 62404248) and the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0302300).

Impact of surface passivation on the electrical stability of strained germanium devices

Zong-Hu Li(李宗祜)1,2, Mao-Lin Wang(王茂粼)1,2, Zhen-Zhen Kong(孔真真)3,4,5,6, Gui-Lei Wang(王桂磊)3,5,6,‡, Yuan Kang(康原)1,2, Yong-Qiang Xu(徐永强)1,2, Rui Wu(吴睿)1,2, Tian-Yue Hao(郝天岳)1,2, Ze-Cheng Wei(魏泽成)1,2, Bao-Chuan Wang(王保传)1,2, Hai-Ou Li(李海欧)1,2,5, Gang Cao(曹刚)1,2,5,†, and Guo-Ping Guo(郭国平)1,2,5,7   

  1. 1 CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China;
    2 CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China;
    3 Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China;
    4 Institute of Microelectronics, University of Chinese Academy of Sciences, Beijing 100049, China;
    5 Hefei National Laboratory, Hefei 230088, China;
    6 Beijing Superstring Academy of Memory Technology, Beijing 100176, China;
    7 Origin Quantum Computing Company Limited, Hefei 230088, China
  • Received:2025-02-17 Revised:2025-04-22 Accepted:2025-05-07 Online:2025-08-21 Published:2025-09-04
  • Contact: Gang Cao, Gui-Lei Wang E-mail:gcao@ustc.edu.cn;guilei.wang@bjsamt.org.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 92265113, 12034018, 12474490, and 62404248) and the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0302300).

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摘要： Strained germanium hole spin qubits are promising for quantum computing, but the devices hosting these qubits face challenges from high interface trap density, which originates from the naturally oxidized surface of the wafer. These traps can degrade the device stability and cause an excessively high threshold voltage. Surface passivation is regarded as an effective method to mitigate these impacts. In this study, we perform low-thermal-budget chemical passivation using the nitric acid oxidation of silicon method on the surface of strained germanium devices and investigate the impact of passivation on the device stability. The results demonstrate that surface passivation effectively reduces the interface defect density. This not only improves the stability of the device's threshold voltage but also enhances its long-term static stability. Furthermore, we construct a band diagram of hole surface tunneling at the static operating point to gain a deeper understanding of the physical mechanism through which passivation affects the device stability. This study provides valuable insights for future optimization of strained Ge-based quantum devices and advances our understanding of how interface states affect device stability.

关键词: hole, strained germanium, interface trap, stability, surface passivation

Abstract: Strained germanium hole spin qubits are promising for quantum computing, but the devices hosting these qubits face challenges from high interface trap density, which originates from the naturally oxidized surface of the wafer. These traps can degrade the device stability and cause an excessively high threshold voltage. Surface passivation is regarded as an effective method to mitigate these impacts. In this study, we perform low-thermal-budget chemical passivation using the nitric acid oxidation of silicon method on the surface of strained germanium devices and investigate the impact of passivation on the device stability. The results demonstrate that surface passivation effectively reduces the interface defect density. This not only improves the stability of the device's threshold voltage but also enhances its long-term static stability. Furthermore, we construct a band diagram of hole surface tunneling at the static operating point to gain a deeper understanding of the physical mechanism through which passivation affects the device stability. This study provides valuable insights for future optimization of strained Ge-based quantum devices and advances our understanding of how interface states affect device stability.

Key words: hole, strained germanium, interface trap, stability, surface passivation

中图分类号:  (Quantum computation architectures and implementations)

  • 03.67.Lx
42.50.Wk (Mechanical effects of light on material media, microstructures and particles) 68.65.Hb (Quantum dots (patterned in quantum wells)) 42.60.Da (Resonators, cavities, amplifiers, arrays, and rings)