Understanding decoherence mechanisms in tantalum-based superconducting qubits

ORAL

Abstract

Tantalum is a promising material platform for superconducting resonators and qubits, with longer coherence times than other commonly used materials including Nb and Al. In this work, we demonstrate that pure α-tantalum can be grown on silicon either with a Nb seed layer at ambient temperature, or without a seed layer at high substrate temperatures. We perform extensive materials characterization including XPS, XRD, SEM, and cross-sectional TEM to understand the characteristics of α-tantalum on silicon. We fabricate superconducting qubits on such films and correlate changes in the fabrication process with changes in both the materials properties and cryogenic device performance. The work here will provide a pathway to fabricate high coherence superconducting qubits based on tantalum on silicon.

*This work was funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under Contract No. DE-AC02-05-CH11231 "High Coherence Multilayer Superconducting Structures for Large Scale Qubit Integration and Photonic Transduction program (QIS-LBNL). Work at the Molecular Foundry was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02- 05CH11231 (SEM, TEM, and XPS characterization and data analysis).

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Presenters

  • Candice Kang

    • University of California, Berkeley

Authors

  • Candice Kang

    • University of California, Berkeley

  • Larry Chen

    • University of California, Berkeley

  • Maria Virginia P Altoe

    • Lawrence Berkeley National Laboratory

  • Kan-Heng Lee

    • Lawrence Berkeley National Laboratory

  • Christian Jünger

    • Lawrence Berkeley National Laboratory
    • University of California, Berkeley

  • Trevor Chistolini

    • University of California, Berkeley

  • D. Frank Ogletree

    • Lawrence Berkeley National Laboratory
    • Molecular Foundry, Lawrence Berkeley National Laboratory

  • Chengyu Song

    • Lawrence Berkeley National Laboratory

  • David I Santiago

    • Lawrence Berkeley National Laboratory

  • Irfan Siddiqi

    • University of California, Berkeley
    • Lawrence Berkeley National Laboratory