INSITU SINGLE-CHAMBER LASER PROCESSING OF YBA2CU3O7-DELTA SUPERCONDUCTING THIN-FILMS ON YTTRIA-STABILIZED ZIRCONIA BUFFERED (100)GAAS

Superconducting YBa2Cu3O7-delta(YBCO) thin films have been deposited in situ on GaAs(100) by laser evaporation using yttria-stabilized zirconia (YSZ) as a buffer layer. The YSZ buffer layer was deposited at room temperature initially, followed by a deposition at 650-degrees-C. The YBCO layers were deposited subsequently at substrate temperature of 650-degrees-C. All the depositions were carried out in a single chamber equipped with a multitarget holder using KrF excimer laser, lambda = 248 nm. The morphology and structure of the buffer layer and YBCO films were determined using x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Auger spectroscopy. The nature of YSZ films was determined to be polycrystalline with partial texturing. The YBCO superconducting thin films on these YSZ-coated GaAs specimens exhibited strong (00l) orientation with peak intensities similar to those observed on single-crystal YSZ substrates. The superconducting transition temperature T(c) (onset) of 92 K and T(c0)(zero resistance) of 73 K were achieved for YBCO thin films on GaAs with YSZ buffer layers.