Preparation of YBaCuO thin films with excellent crystallinity on amorphous substrates prepared by facing targets sputtering

YBa₂Cu₃O_x (YBCO) thin films with almost perfect orientation were prepared on amorphous fused quartz substrates by a facing targets sputtering (FTS) system without a detectable difference in composition between targets and films. The lowest substrate temperatures at which clear c-axis orientation and evident crystallite growth were attained were 490°C and 580°C. However, the films deposited on MgO exhibited a modulation structure with spacing of 4.2 A in thickness direction normal to the film plane, whereas the films deposited on fused quartz did not exhibit such a modulation structure. The film deposited on fused quartz at substrate temperatures as low as 600°C had a T_c as high as 94 K with perfect c-axis orientation and excellent surface smoothness. Consequently, the FTS system may be suitable for fabricating such superconductive oxide films, even on amorphous substrates