PREPARATION OF LARGE-AREA Y1BA2CU3O7-X EPITAXIAL THIN-FILMS AND HIGH-T-C SUPERCONDUCTING MICROWAVE DEVICE CHARACTERISTICS

Superconducting Y1Ba2Cu3O7-x. films were fabricated on 20x20-mm(2), 1- inch diameter (001) MgO substrates by using an in situ DG hollow catho de sputtering system. The X-ray diffraction theta-2 theta scan pattern s and phi scans showed good crystallinity for the films with c-axis gr owth. The thickness variation and the cationic composition were measur ed as a function of the substrate radius for the YBCO thin films on 3- inch Si wafers. The YBCO films deposited on nine slices of the MgO sub strates within the area of a 40-mm-diamater circle showed critical tem peratures of 84 similar to 88 K and critical current densities of 1 si milar to 2x10(6) A/cm(2) at 77 K. The surface resistance was 1.9 m Ome ga at 77 K and 4 GHz. The microwave response characteristic of a high- T-c superconducting 9-pole low-pass filter was also investigated.