Minimizing Kinetic Inductance in Tantalum-Based Superconducting Coplanar Waveguide Resonators for Alleviating Frequency Fluctuation Issues

Advancements in thefabrication of superconducting quantum devices have highlighted tantalum as apromising material, owing to its low surface oxidation microwave loss at lowtemperatures. However, tantalum films exhibit significantly larger kineticinductances compared to materials such as aluminum or niobium. Given theinevitable variations in film thickness, this increased kinetic inductanceleads to considerable, uncontrolled frequency variances and shifts incomponents like superconducting coplanar waveguide resonators. Achieving highprecision in resonator frequencies is crucial, particularly when multiple resonatorsshare a common Purcell filter with limited bandwidth in superconducting quantuminformation processors. Here, we tackle this challenge from both fabricationand design perspectives, achieving a reduction in resonator frequencyfluctuation by 100 fold. Concurrently, the internal quality factor of thesuperconducting coplanar waveguide resonator remains at high level. Ourfindings open up new avenues for the enhanced utilization of tantalum inlarge-scale superconducting chips.

                                           Overviewof the system under investigation and the optimization results

Article：arXiv:2405.02955v1