Ion-beam-assisted texturing of YSZ layers

For high-current carrying YBa2Cu3O7-x films, biaxially textured yttria-stabilized zirconia (YSZ) films serve as templates. The YSZ layers are textured by an ion-beam-assisted deposition process (IBAD). Our present investigations of the texture evolution indicated a sequence of at least three characteristic growth stages. During an initial stage, wire-textured (011)-oriented grains nucleated. This stage was followed by a transition stage where (DOI)-oriented grains grew epitaxially on (011) grains which were favorably oriented with respect to the assisting beam. During the final stage a growth selection led to an improvement of the in-plane alignment of those (001)-oriented grains with their (111) axis parallel to the assisting beam. Each one of these growth stages was dominated by specific underlying mechanisms which have been identified. Internal film stresses caused by the massive bombardment of the assisting beam might influence the orientation of nuclei. Ion-beam-induced homoepitaxy generated epitaxial relations between nuclei and underlying film layers. Finally, anisotropic sputter rates caused alterations in growth rates of differently oriented grains that led to an overgrowth of misoriented grains. These results will be summarized in the form of a schematic growth model for IBAD-YSZ films. (C) 2002 Elsevier Science B.V. All rights reserved.