Atomic Force Microscopy of Surface Reconstructed SrTiO₃ Vicinal Substrates for Epitaxial Growth of YBa₂Cu₃O_7-δ Thin Films

SrTiO₃(001) vicinal substrates of miscut 1°, 3°, and 6° toward the (001) plane were annealed at 800-1000°C in pure flowing O₂ for 6h and examined by atomic force microscopy. The high temperature annealed vicinal SiTiO₃(001) displayed arrays of straight steps and smooth terraces. The step heights vary from about 2 to 6 unit cell depending on the annealing temperatures. At 1000°C, step bunching becomes obvious. The height steps of 1 unit cell are difficult to be observed by our atomic force microscopy. The YBa₂Cu₃O_7-δ thin film grows epitaxially on the step-terrace surface with c-axis orientation by magnetron sputtering in the two-dimensional island mode. Prospect of step-flow growth is being discussed.