THE RELATION BETWEEN THE DEFECT STRUCTURE, THE SURFACE-ROUGHNESS AND THE GROWTH-CONDITIONS OF YBA2CU3O7-DELTA FILMS

YBa2Cu3O7-delta films on SrTiO3 are characterized by a network of anti -phase boundaries (APB's), protruding from the interface to the film s urface. We propose that the island morphology of these films is to a l arge extent determined by this network. At APE-outcrops deep trenches form which separate the growth islands. At the cross-section of three APB's deep holes are formed. It is found that the growth island size c an be increased by increasing the substrate temperature or the oxygen pressure during growth.