中国物理B ›› 2024, Vol. 33 ›› Issue (9): 90310-090310.doi: 10.1088/1674-1056/ad6a3c

所属专题： SPECIAL TOPIC — Quantum computing and quantum sensing

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In-situ deposited anti-aging TiN capping layer for Nb superconducting quantum circuits

Hao-Ran Tao(陶浩然)1,2, Lei Du(杜磊)1,2, Liang-Liang Guo(郭亮亮)1,2, Yong Chen(陈勇)1,2, Hai-Feng Zhang(张海峰)1,2, Xiao-Yan Yang(杨小燕)1,2, Guo-Liang Xu(徐国良)3, Chi Zhang(张 驰)3, Zhi-Long Jia(贾志龙)3, Peng Duan(段鹏)1,2,†, and Guo-Ping Guo(郭国平)1,2,3,‡   

  1. 1 CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China;
    2 CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China;
    3 Origin Quantum Computing Company Limited, Hefei 230088, China
  • 收稿日期:2024-06-18 修回日期:2024-07-29 接受日期:2024-08-02 发布日期:2024-08-30
  • 通讯作者: Peng Duan, Guo-Ping Guo E-mail:pengduan@ustc.edu.cn;gpguo@ustc.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12034018 and 11625419).

In-situ deposited anti-aging TiN capping layer for Nb superconducting quantum circuits

Hao-Ran Tao(陶浩然)1,2, Lei Du(杜磊)1,2, Liang-Liang Guo(郭亮亮)1,2, Yong Chen(陈勇)1,2, Hai-Feng Zhang(张海峰)1,2, Xiao-Yan Yang(杨小燕)1,2, Guo-Liang Xu(徐国良)3, Chi Zhang(张 驰)3, Zhi-Long Jia(贾志龙)3, Peng Duan(段鹏)1,2,†, and Guo-Ping Guo(郭国平)1,2,3,‡   

  1. 1 CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China;
    2 CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China;
    3 Origin Quantum Computing Company Limited, Hefei 230088, China
  • Received:2024-06-18 Revised:2024-07-29 Accepted:2024-08-02 Published:2024-08-30
  • Contact: Peng Duan, Guo-Ping Guo E-mail:pengduan@ustc.edu.cn;gpguo@ustc.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12034018 and 11625419).

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摘要： The performance of Nb superconducting quantum devices is predominantly limited by dielectric loss at the metal-air interface, where Nb$_2$O$_5$ is considered the main loss source. Here, we suppress the formation of native oxides by in-situ deposition of a TiN capping layer on the Nb film. With TiN capping layers, no Nb$_2$O$_5$ forms on the surface of the Nb film. The quality factor $Q_{\rm i}$ of the Nb resonator increases from $5.6\times10^{5}$ to $7.9\times10^{5}$ at low input power and from $6.8\times10^{6}$ to $1.1\times10^{7}$ at high input power. Furthermore, the TiN capping layer also shows good aging resistance in Nb resonator devices, with no significant performance fluctuations after one month of aging. These findings highlight the effectiveness of TiN capping layers in enhancing the performance and longevity of Nb superconducting quantum devices.

关键词: anti-aging, oxidation, dielectric loss, Nb superconducting quantum circuits

Abstract: The performance of Nb superconducting quantum devices is predominantly limited by dielectric loss at the metal-air interface, where Nb$_2$O$_5$ is considered the main loss source. Here, we suppress the formation of native oxides by in-situ deposition of a TiN capping layer on the Nb film. With TiN capping layers, no Nb$_2$O$_5$ forms on the surface of the Nb film. The quality factor $Q_{\rm i}$ of the Nb resonator increases from $5.6\times10^{5}$ to $7.9\times10^{5}$ at low input power and from $6.8\times10^{6}$ to $1.1\times10^{7}$ at high input power. Furthermore, the TiN capping layer also shows good aging resistance in Nb resonator devices, with no significant performance fluctuations after one month of aging. These findings highlight the effectiveness of TiN capping layers in enhancing the performance and longevity of Nb superconducting quantum devices.

Key words: anti-aging, oxidation, dielectric loss, Nb superconducting quantum circuits

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

  • 03.67.Lx
03.67.-a (Quantum information)