Atomic-scale Analysis of Laser MBE Growth of Oxide Thin Films by in situ Rheed and Caiciss

Abstract

ABSTRACTAtomic-scale growth analysis of oxide thin films was performed by in situ reflection high energy electron diffraction (RHEED) and coaxial impact collision ion scattering spectroscopy (CAICISS) combined with Laser MBE. On single crystal substrates with atomically flat terrace and step structures, the two-dimensional nucleation followed by molecular layer-by-layer growth was verified by in situ monitoring of RHEED intensity oscillations, as well as ex situ atomic force microscopy (AFM) observation, for the growth of BaTiO3, Al2O3 and BaO thin films. The epitaxial BaTiO3 films grown on SrTiO3(100) and c-axis oriented Bi2Sr2CaCu2Ox (Bi2212) superconducting films were subjected to in situ CAICISS measurements in order to examine the topmost surface structure. The key factors to develop oxide lattice engineering are discussed with respect to not only in situ monitoring of the growth process using RHEED but also the atomic regulation of the substrate surface by AFM and ion scattering spectroscopy. The present work also demonstrates the advanced oxide thin film processing based on the laser MBE to control the growth and surface of films on an atomic scale.