We have investigated the correlation between the microwave loss and patterning method for coplanar waveguide titanium nitride resonators fabricated on Si wafers. Three different methods were investigated: fluorine- and chlorine-based reactive ion etches and an argon-ion mill. At high microwave probe powers the reactive etched resonators showed low internal loss, whereas the ion-milled samples showed dramatically higher loss. At single-photon powers we found that the fluorine-etched resonators exhibited substantially lower loss than the chlorine-etched ones. We interpret the results by use of numerically calculated filling factors and find that the silicon surface exhibits a higher loss when chlorine-etched than when fluorine-etched. We also find from microscopy that re-deposition of silicon onto the photoresist and side walls is the probable cause for the high loss observed for the ion-milled resonators
@article{arxiv.1205.3153,
title = {Etch Induced Microwave Losses in Titanium Nitride Superconducting Resonators},
author = {Martin Sandberg and Michael R. Vissers and Jeffrey S. Kline and Martin Weides and Jiansong Gao and David S. Wisbey and David P. Pappas},
journal= {arXiv preprint arXiv:1205.3153},
year = {2016}
}