, Jeffrey S. Kline, , ,
We have investigated the correlation between the microwave loss and patterning method for coplanar waveguide titanium nitride resonators fabricated on silicon 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.
Applied Physics Letters
etch, low loss, superconducting resonator, Titanium Nitride