Laser surface interaction during and after deposition of thin oxide films

Thin films of PZT (Pb(Zr0.54Ti0.46)O-3) were deposited by KrF and XeCl excimer laser ablation onto platinated silicon wafers (Si/Pt) and yttrium stabilized zirconia (YSZ) covered with YBa2Cu3O7-x (YSZ/YBCO). The substrate temperature (T-s) ranged from 240 to 720 degrees C and the substrate surface was optionally activated by excimer laser irradiation (ArF, KrF) during deposition. On Si/Pt substrates PZT showed permittivity values of epsilon less than or equal to 200 only, with ArF laser activation (20 mJ/cm(2), T-s = 360 degrees C) epsilon = 360. On YSZ/YBCO samples, ferroelectric PZT of dominantly perovskite crystal structure was obtained at T-s = 500-700 degrees C with epsilon less than or equal to 750. With surface activation (ArF: less than or equal to 35 mJ/cm(2), KrF: less than or equal to 85 mJ/cm(2)) at T-s = 350-500 degrees C PZT showed epsilon = 500-1200. In dc SQUIDs one Josephson junction was selectively heated above T-c by Ar+ laser irradiation to measure the critical current of the second junction individually. At high Ar+ laser intensity O-2 effusion from YBCO was used to narrow the junction width in steps of 1 mu m. The width reduction from 23 to 9 mu m in both junctions resulted in a flat baseline of the SQUID and an increase of the voltage modulation amplitude from 8 to 12 mu V. Passivation layers for YBCO consisting of AuOx, PtOx, and AuAgOx showed O-2 effusion upon Ar+ laser irradiation depending on the laser intensity, The electrical contact resistance decreased from 10(-2) Omega cm(2) to 5 x 10(-7) Omega cm(2) when converting AuAgOx to AuAg. The superconductivity in YBCO under the laser modified contact was completely preserved.