Chemical Profiles of the Oxides on Tantalum in State of the Art Superconducting Circuits
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- Department of Electrical and Computer Engineering Princeton University Princeton NJ 08544 USA
- Center for Functional Nanomaterials Brookhaven National Laboratory Bldg. 735, P.O. Box 5000 Upton NY 11973‐5000 USA
- Materials Measurement Science Division, Material Measurement Laboratory National Institute of Standards and Technology Gaithersburg MD 20899 USA
- Department of Chemistry Princeton University Princeton NJ 08544 USA
- Department of Physics Princeton University Princeton NJ 08544 USA
- National Synchrotron Light Source II Brookhaven National Laboratory Bldg 740 Upton NY 11973‐5000 USA
Abstract Over the past decades, superconducting qubits have emerged as one of the leading hardware platforms for realizing a quantum processor. Consequently, researchers have made significant effort to understand the loss channels that limit the coherence times of superconducting qubits. A major source of loss has been attributed to two level systems that are present at the material interfaces. It is recently shown that replacing the metal in the capacitor of a transmon with tantalum yields record relaxation and coherence times for superconducting qubits, motivating a detailed study of the tantalum surface. In this work, the chemical profile of the surface of tantalum films grown on c‐plane sapphire using variable energy X‐ray photoelectron spectroscopy (VEXPS) is studied. The different oxidation states of tantalum that are present in the native oxide resulting from exposure to air are identified, and their distribution through the depth of the film is measured. Furthermore, it is shown how the volume and depth distribution of these tantalum oxidation states can be altered by various chemical treatments. Correlating these measurements with detailed measurements of quantum devices may elucidate the underlying microscopic sources of loss.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Office of Workforce Development for Teachers & Scientists (WDTS)
- Grant/Contract Number:
- SC0012704
- OSTI ID:
- 1973289
- Report Number(s):
- BNL--224421-2023-JAAM; 2300921
- Journal Information:
- Advanced Science, Journal Name: Advanced Science Journal Issue: 21 Vol. 10; ISSN 2198-3844
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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