Dielectric Relaxation Study of Hydrogen Exposure as a Source of Two-Level Systems in Al2O3
An important question in the manufacture of superconducting electronics is how to control the two-level systems found in amorphous insulators. The present article shows that hydrogen has a marked impact on the two-level systems in thin films of reactively sputtered Al2O3, a standard tunnel oxide for Josephson junctions. The magnitude of dielectric relaxation current in Al2O3 films, believed to be caused by two-level systems, is shown to increase monotonically with the flow rate of H2 into the chamber during deposition. This points toward a potential need for controlling hydrogen during the manufacture of superconducting electronics utilizing Al2O3.
Jameson, J. R., Ngo, D., Benko, C., McVittie, J. P., Nishi, Y., & Young, B. A. (2011). Dielectric relaxation study of hydrogen exposure as a source of two-level systems in Al2O3. Journal of Non-Crystalline Solids, 357(10), 2148–2151. https://doi.org/10.1016/j.jnoncrysol.2011.02.054