Process Optimization for Superconducting Resonators via Identification and Mitigation of Interface Loss Mechanisms

ORAL

Abstract

CPW resonators plays a vital role for many quantum circuits. They also serve as a platform to characterize loss mechanisms in superconducting materials in the microwave frequency range. We report on the characterization and iterative process development of niobium-based CPW resonators. Using a set of post-fabrication chemical etching techniques, we have systematically reduced the metal-air and substrate-air oxide thickness, improving the device quality factor beyond 5 million at single-photon-excitation power (measured at 100 mK). Following these low temperature electrical measurements, resonator samples have been probed using a suite of structural characterization tools (XPS, TEM and AFM) in order to determine the thickness, chemical composition and location of parasitic interface layers and their contribution towards quality factor.

*This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under Contract No. DE-AC02-05-CH11231 within the QISLBNL program.

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Presenters

  • Archan Banerjee

    • Lawrence Berkeley National Laboratory
    • University of California, Berkeley

Authors

  • Archan Banerjee

    • Lawrence Berkeley National Laboratory
    • University of California, Berkeley

  • AHMED HAJR

    • Lawrence Berkeley National Laboratory

  • Cassidy Berk

    • Lawrence Berkeley National Laboratory

  • John Mark Kreikebaum

    • Lawrence Berkeley National Laboratory
    • University of California, Berkeley
    • Univ of California – Berkeley
    • Physics, University of California, Berkeley

  • Virginia Altoe

    • Lawrence Berkeley National Laboratory

  • David Ivan Santiago

    • Lawrence Berkeley National Laboratory
    • University of California, Berkeley
    • Lawrence Berkely National Laboratory
    • Quantum Nanoelectronics Laboratory, Dept. of Physics, University of California, Berkeley

  • D. Frank Ogletree

    • Lawrence Berkeley National Laboratory

  • Irfan Siddiqi

    • Lawrence Berkeley National Laboratory
    • University of California, Berkeley
    • Univ of California - Berkeley
    • Univ of California – Berkeley
    • Quantum Nanoelectronics Lab, UC Berkeley
    • Physics, University of California, Berkeley
    • Quantum Nanoelectronics Laboratory, Dept. of Physics, University of California, Berkeley