Microwave characterization of coplanar waveguide transmission lines fabricated by ion implantation patterning of YBa/sub 2/Cu/sub 3/O/sub 7-δ/

Abstract

We report on the application of Si and Al ion-implantation patterning to the fabrication of low-loss microwave transmission lines in high-temperature superconductor (HTS) thin films. Using this technique, we have fabricated coplanar waveguide (CPW) transmission lines in YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) thin films deposited on LaAlO/sub 3/ substrates. We have used both resonant and broadband measurements in order to characterize the performance of the resulting transmission line structures. For the broadband measurements, on-wafer calibrations were used to obtain accurate S-parameters and transmission line propagation constants up to 25 GHz. The propagation constants of the ion-implanted transmission lines do not differ significantly from those of lines patterned using conventional ion milling over the frequency range studied, with a value for the attenuation constant of approximately 0.03-0.04 dB/cm at 50 K and 10 GHz. The relatively low losses of the ion-implanted devices demonstrate the effectiveness of this method of patterning for HTS microwave device fabrication.