HIGH-TC THIN-FILMS WITH ROUGHNESS SMALLER THAN ONE UNIT-CELL

We have developed a method for the growth of epitaxial high T(c) superconducting thin films with roughness smaller than one unit cell using conventional magnetron sputtering. In this method the substrate is positioned above one edge of the target (off axis) to avoid resputtering, and oscillated back and forth between the two symmetrical edges of the target to improve film thickness homogeneity. Finite size peaks in the x-ray diffraction spectra of thin GdBa2Cu3O7-delta films and satellite peaks on a GdBa2Cu3O7-delta/YBa2Cu3O7-delta superlattice show the excellent thickness control and smoothness obtained with this technique.