SURFACE TOPOGRAPHY ON EPITAXIAL HoBa₂Cu₃O_7-δ AND Bi₂Sr₂CaCu₂O_8+δ THIN FILMS

Abstract

Surface topography on epitaxial HoBa 2 Cu 3 O 7-δ (HBCO) and Bi 2 Sr 2 CaCu 2 O 8+δ (BSCCO) thin films analysis by using the atomic force microscopy (AFM) technique was carried out. The films were deposited in situ on SrTiO 3 substrates with thicknesses ranging from 100 to 300 nm by a high-pressure sputtering process. Chemical etching with a nonaqueous solution of Br-ethanol was used to modify the surface of the samples. HBCO films showed spiral grains, while BSCCO samples exhibited a terraced growth. Etching with Br-ethanol has different effects on HBCO and BSCCO. In HBCO, etching produces clean surfaces with light changes on the surface morphology, whereas in BSCCO it conduces to strong changes in the structure and the roughness of the film surface.