XPS STUDY OF THE INTERFACE REACTIONS BETWEEN BUFFER LAYERS FOR HTSC THIN-FILMS AND SILICON

In this work we have studied the interface reactions during e-beam evaporation of yttria-stabilized zirconia (YSZ), yttria (Y2O3) and Y on Si(100) substrates by means of x-ray photoelectron spectroscopy (XPS). A deposition process was developed for the heteroepitaxial growth of YSZ and Y2O3. A high amount of metallic Zr in the YSZ vapour results in an in situ reduction of the native silicon oxide layer, allowing the growth of high-quality YSZ films even on uncleaned Si substrates. A similar in situ reduction process was achieved for the Y2O3 film growth on uncleaned substrates by a predeposition of metallic Y. The deposition of YBa2Cu3O7-delta (YBCO) films on YSZ/Y2O3/Si multilayers by dc magnetron sputtering resulted in critical current densities of the YBCO layer in excess of 2 x 10(6) A cm-2.