Substrate and process dependent losses in superconducting thin film resonators

作者：Wei Chen, D. A. Bennett, Vijay Patel, James E. Lukens · 发表于：Superconductor Science and Technology · 年份：2008 · DOI：10.1088/0953-2048/21/7/075013 · 被引用次数：56 · 研究领域：Physics of Superconductivity and Magnetism、Superconducting and THz Device Technology、Advanced Frequency and Time Standards

We measured the quality factor (Q) and hence the losses of thin film superconducting Nb coplanar waveguide resonators fabricated with processes and materials similar to those used for Josephson effect qubits, where such losses can cause significant decoherence. Intrinsic Q-values range from several thousand to almost 106 depending on the process details. Reactive ion etching appears to reduce the resonator Q-values and the lift-off process can also degrade the Q-value for some resists. The resistivity of the Si substrates affects the intrinsic Q at 1 K, where the resonators were measured. The Q-values obtained for optimized processing are sufficiently high as to suggest that qubits fabricated by a similar technique would not be limited by losses associated with the film or substrate.