APS Logo

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.

–

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