Fabrication-induced decoherencein superconducting coplanar waveguide resonators

摘要: High quality factor superconducting coplanar waveguide resonators (CPWR) provide crucial elementforquantum memory [1], parametric amplifiers [2] and quantum electrodynamics circuits [3]. Such applicationsarelimited by the CPWR intrinsic quality factor [4]. High quality factor coplanar resonators performance is sensitive to design, fabrication and characterization techniques that makeits manufacturing quite challenging. Recent studies show that devices relaxation time is drastically reduced by dielectric loss and fluctuations due to two-level system (TLS) tunneling defects [4]. Using CPWR as sensitive probes, we investigate the sources of capacitive losses, arisen from imperfections at substrate-metal, substrate-vacuum, metal-vacuum interfaces and carefully optimize our manufacturing processes. RemovingTLS sources from the interfaces withadvancedsubstrate surface treatment, epitaxialaluminum films [5], non-damage etching anddevice post cleaning, wehas achieved CPWRs with extremely low dissipation.