Probing Microstructure, Superconducting Properties and Disorder in NbN Thin Films Using Kinetic Inductance Devices

ORAL

Abstract

Superconducting transition metal nitrides such as NbN and TiN are promising for next-generation quantum technologies due to their high critical temperature (Tc), negligible native oxide formation, kinetic inductance tunability and compatibility with semiconductor fabrication processes. Achieving optimal performance requires precise control of thin-film growth to tailor crystallinity, stoichiometry, and defect density. Here, we present a systematic study of NbN films grown by DC reactive sputtering at Berkeley Lab’s Molecular Foundry, combining structural, chemical, and electrical characterization to directly correlate microstructure and composition with superconducting properties. By varying substrate choice, deposition temperature, and nitrogen partial pressure, we probe their influence on crystallinity, composition and high-Tc phase formation. Kinetic inductance resonators further reveal the impact of disorder on microwave performance through power- and temperature-dependent quality factor measurements. This work establishes a robust framework for the design, synthesis, and optimization of high-quality superconducting nitride films for scalable quantum circuits and devices.

*Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231

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Presenters

  • Mythili Surendran

    • Lawrence Berkeley National Laboratory

Authors

  • Mythili Surendran

    • Lawrence Berkeley National Laboratory

  • Yashwanth Balaji

    • Lawrence Berkeley National Laboratory

  • Zi-Huai Zhang

    • University of California, Berkeley
    • University of California, Berkeley and Lawrence Berkeley National Laboratory
    • Princeton University

  • Xinran Li

    • Lawrence Berkeley National Laboratory

  • Alexander Herman

    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory, University of California Berkeley

  • Aidar Kemelbay

    • Lawrence Berkeley National Laboratory

  • Arian Gashi

    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab

  • Alp Sipahigil

    • University of California, Berkeley
    • University of California, Berkeley and Lawrence Berkeley National Laboratory

  • Aeron T Hammack

    • Lawrence Berkeley National Labs

  • Shaul Aloni

    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab

  • Adam Schwartzberg

    • Angstrom Engineering Inc.
    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab