INSITU GROWTH OF HIGH-TEMPERATURE SUPERCONDUCTOR THIN-FILMS WITH EVAPORATION TECHNIQUES USING AN OZONE JET

High quality YBa2Cu3O7 thin films are grown in situ on various substrates (SrTiO3, AI2O3, Si) using MBE techniques and an ozone jet. The yttrium and copper are evaporated from electron gun sources and the barium is evaporated from a Knudsen cell. All sources are controlled by a single mass spectrometer feedback system to obtain the correct fluxes at high partial ozone pressures. During deposition the partial ozone pressure at the substrate position is estimated to be 10-3-10-2 mbar. The substrate holder temperature is 700 °C. The films are analyzed with R(T), X-ray diffraction and RBS measurements. SEM photographs are taken of the surface. The best film so far is grown on SrTiO3 and has a Tc,onset of 88 K and a TcO of 80 K. One 200 nm thick film grown on bare silicon has a Tcset of 88 K and a TcO of 60 K. This film shows negligible superconductor-substrate interactions according to the RBS measurements. © 1990.