PROCESSING AND YIELD OF Y1BA2CU3O7-X THIN-FILMS AND DEVICES PRODUCED WITH A BAF2 PROCESS

High quality films were produced by co-evaporation and co-sputtering of Y, Cu, and BaF2 followed by an ex-situ anneal. The Y1Ba2Cu3O7-x films produced had microwave surface resistances as low as 1/10 that of Cu at 77 K and 10 GHz. This process is especially useful for producing uniform films over areas larger than 1 square inch and is compatible with lift-off or traditional etch patterning processes for fabrication of microwave devices. More than 100 films have been deposited on (100) LaAlO3 with various compositions and anneal conditions. Films were characterized by a wide variety of techniques aimed at optimization of film quality through process control. Emphasis was placed on determining the relationship between material properties and film microwave performance. Run-to-run reproducibility for a sample set of over 20 films was determined. In addition, C-band 5 GHz microstrip resonators were fabricated from these microwave characterized films. Unloaded Q's of these devices have exceeded 7500 at 77 K compared to normal metal resonator Q's of 300 for this structure. These Q's correlate well with predicted performance based upon the previously measured microwave surface resistance of the unpatterned films.