中国物理B ›› 2017, Vol. 26 ›› Issue (9): 98501-098501.doi: 10.1088/1674-1056/26/9/098501

• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

Modulation depth of series SQUIDs modified by Josephson junction area

Jie Liu(刘杰), He Gao(高鹤), Gang Li(李刚), Zheng Wei Li(李正伟), Kamal Ahmada, Zhang Ying Shan(张颖珊), Jian She Liu(刘建设), Wei Chen(陈炜)   

  1. 1 Tsinghua National Laboratory for Information Science and Technology, Department of Microelectronics and Nanoelectronics, Institute of Microelectronics, Tsinghua University, Beijing 100084, China;
    2 Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China;
    3 University of Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2017-03-29 修回日期:2017-05-24 出版日期:2017-09-05 发布日期:2017-09-05
  • 通讯作者: Wei Chen E-mail:weichen@tsinghua.edu.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant No. 11653001), the National Basic Research Program of China (Grant No. 2011CBA00304), and Tsinghua University Initiative Scientific Research Program, China (Grant No. 20131089314).

Modulation depth of series SQUIDs modified by Josephson junction area

Jie Liu(刘杰)1, He Gao(高鹤)2,3, Gang Li(李刚)1, Zheng Wei Li(李正伟)2, Kamal Ahmada1, Zhang Ying Shan(张颖珊)1, Jian She Liu(刘建设)1, Wei Chen(陈炜)1   

  1. 1 Tsinghua National Laboratory for Information Science and Technology, Department of Microelectronics and Nanoelectronics, Institute of Microelectronics, Tsinghua University, Beijing 100084, China;
    2 Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China;
    3 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2017-03-29 Revised:2017-05-24 Online:2017-09-05 Published:2017-09-05
  • Contact: Wei Chen E-mail:weichen@tsinghua.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant No. 11653001), the National Basic Research Program of China (Grant No. 2011CBA00304), and Tsinghua University Initiative Scientific Research Program, China (Grant No. 20131089314).

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摘要：

The superconducting quantum interference device (SQUID) amplifier is widely used in the field of weak signal detection for its low input impedance, low noise, and low power consumption. In this paper, the SQUIDs with identical junctions and the series SQUIDs with different junctions were successfully fabricated. The Nb/Al-AlOx/Nb trilayer and input Nb coils were prepared by asputtering equipment. The SQUID devices were prepared by a sputtering and the lift-off method. Investigations by AFM, OM and SEM revealed the morphology and roughness of the Nb films and Nb/Al-AlOx/Nb trilayer. In addition, the current-voltage characteristics of the SQUID devices with identical junction and different junction areas were measured at 2.5 K in the He3 refrigerator. The results show that the SQUID modulation depth is obviously affected by the junction area. The modulation depth obviously increases with the increase of the junction area in a certain range. It is found that the series SQUID with identical junction area has a transimpedance gain of 58 Ω approximately.

关键词: superconducting quantum interference device (SQUID), Josephson junction, transition edge sensor

Abstract:

The superconducting quantum interference device (SQUID) amplifier is widely used in the field of weak signal detection for its low input impedance, low noise, and low power consumption. In this paper, the SQUIDs with identical junctions and the series SQUIDs with different junctions were successfully fabricated. The Nb/Al-AlOx/Nb trilayer and input Nb coils were prepared by asputtering equipment. The SQUID devices were prepared by a sputtering and the lift-off method. Investigations by AFM, OM and SEM revealed the morphology and roughness of the Nb films and Nb/Al-AlOx/Nb trilayer. In addition, the current-voltage characteristics of the SQUID devices with identical junction and different junction areas were measured at 2.5 K in the He3 refrigerator. The results show that the SQUID modulation depth is obviously affected by the junction area. The modulation depth obviously increases with the increase of the junction area in a certain range. It is found that the series SQUID with identical junction area has a transimpedance gain of 58 Ω approximately.

Key words: superconducting quantum interference device (SQUID), Josephson junction, transition edge sensor

中图分类号:  (Josephson devices)

  • 85.25.Cp
85.25.Dq (Superconducting quantum interference devices (SQUIDs)) 07.20.Mc (Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment)