AFM observations on the growth mechanisms of epitaxial perovskite oxide SrRuO3 thin films

The growth mechanism and surface morphology of epitaxial SrRuO3 thin films deposited on exact and vicinal (001) SrTiO3 and exact (001) LaAlO3 substrates has been studied. Vicinal substrates with miscut angle, alpha, up to 4 degrees toward [010] direction were used. Atomic force microscope images show that the films grown on exact (001) SrTiO3 substrate had a growth mechanism involving two dimensional nucleation. In contrast, characteristic step patterns were observed on the films deposited on vicinal substrates, suggesting that these films had a step flow growth mode. The films deposited on exact (001) LaAlO3 substrates had a three dimensional island growth, due to the incoherence between the film and substrate lattice. These results were found to be consistent with the results of x-ray diffraction analysis of the in-plane domain structure.