Processing and Substrate Effects on YBaCuO Thin Films Formed by Rapid Thermal Annealing of Cu/BaO/Y2O3 Layered Structures

YBaCuO superconducting thin films have been formed by rapid thermal annealing (RTA) of Cu/BaO/Y2O3 layered structures. The films were deposited on various substrates (including MgO, Al2O3 and Si) by electron-beam evaporation. The film properties strongly depend on the annealing conditions as well as the substrate used. We found that with 950 – 990 °C anneal for 30 – 90 seconds, the layers intermixed completely and a YBa2Cu3Ox. polycrystalline film was produced. The best film was obtained on MgO with Tc above 84 K and Jc of 4x103 A/cm2 at 77 K. However, using the same RTA conditions, films on Si showed semiconducting behavior caused by silicon diffusion into the film as indicated by Auger depth profiling. In general, we found that using the RTA process, the film has less film-substrate interaction in comparison with furnace annealing due to a short anneal time. Using the RTA processing with the incorporation of a metal barrier layer, superconductivity of the film on Si was observed. Compared with other techniques, the RTA processing of layered structures provides a simple and rapid method for fabrication of high Tc superconducting thin films.