Grain size in low loss superconducting Ta thin films on c-axis sapphire

Published

October 9, 2023

Author(s)

Corey Rae McRae

Abstract

In recent years, the implementation of thin-film Ta has led to improved coherence times in superconducting circuits. Efforts to further optimize this materials stack have become a focus of the materials for superconducting quantum computing subfield. It has been previously hypothesized that grain size could be correlated with device performance. In this work, we perform a comparative grain size experiment with $\alpha$-Ta on $c$-axis sapphire. Our evaluation methods include both room-temperature chemical and structural characterization and cryogenic microwave measurements, and we report no statistical difference in device performance between small- and larger-grain-size devices with grain sizes of 924 nm$^2$ and 1700 nm$^2$, respectively. These findings suggest that grain size is not correlated with loss in the parameter regime of interest for Ta grown on c-axis sapphire.

Citation

Journal of Applied Physics

Pub Type

Journals

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Keywords

TLS, superconducting microwave resonators, superconducting qubit materials, tantalum

Citation

McRae, C. (2023), Grain size in low loss superconducting Ta thin films on c-axis sapphire, Journal of Applied Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=956260 (Accessed October 28, 2025)