SCANNING FORCE MICROSCOPY STUDY OF THE SURFACE-TOPOGRAPHY OF THIN BATIO3 FILMS DEPOSITED BY PULSED-LASER ABLATION

The surface topography of thin single-crystal BaTiO3 films deposited o n SrTiO3(100) and YBCO(001)/LaAlO3(100) substrates, and thin polycryst alline films deposited on MgO(100) was studied using scanning force mi croscopy in air. Films 0.37, 0.26, and 0.39 mu m thick were grown on t he SrTiO3(100) substrate at 750 degrees C at oxygen pressures of 0.7, 7, and 70 Pa, respectively. Films 0.47, 0.26, and 0.25 mu m thick were deposited on the SrTiO3(100) substrate at the temperatures of 550, 75 0, and 850 degrees C, respectively, at an oxygen pressure of 7 Pa. Fil ms 0.20 and 0.10 mu m thick were grown on MgO(100) and YBCO(001)/LaAlO 3(100) substrates, respectively, at 750 degrees C and 7 Pa. Scanning f orce microscopy images show that, for the deposition temperature of 75 0 degrees C, when the oxygen pressure is increased from 0.7 to 7 and 7 0 Pa, the surface topography of the BaTiO3 films changes from flat to islandlike three-dimensional growth (Volmer-Weber mode), and the corre sponding rms surface roughness values are 1.2, 3.4, and 6.4 nm. With a n increase of the deposition temperature from 550 to 750 and 850 degre es C, the surface topography changes from corrugated to rectangular gr ain, and the corresponding surface roughness values are 1.2, 3.4, and 3.4 nm for an oxygen pressure of 7 Pa. The films on the MgO(100) subst rate consist of two kinds of grains, and the corresponding surface rou ghness value is 1.0 nm. The film on YBCO(001)/LaAlO3(100) substrate is composed of uniform hemispherical grains, and corresponding surface r oughness value is 29 nm due to the roughness of the bare substrate of 31 nm. (C) 1996 American Vacuum Society.