Quantitative Analysis of Surface Losses in Coplanar Waveguide Resonators Part 3: Surface Loss Extraction*

Uniquely characterizing TLS defect layers around superconductors is challenging due to the nearly proportional scaling multiple of the defect layer participations in response to changes in geometry and anisotropic trench depth. We design a set of superconducting coplanar waveguide resonators utilizing deep isotropic etching into the silicon substrate to enable the extraction of independent surface losses. We then combine finite element electromagnetic simulations with statistical characterization of these isotropically etched resonators to determine the independent loss contribution from different interfaces for a high-Q TiN superconductor fabrication process. This characterization technique can be used to quantify the impact of process changes on individual defect layer losses and also as a general process monitor of multiple defect layer losses in co-fabricated superconducting qubit circuits.