REFLECTION HIGH-ENERGY ELECTRON-DIFFRACTION AND ATOMIC-FORCE MICROSCOPY STUDIES ON HOMOEPITAXIAL GROWTH OF SRTIO3(001)

This paper reports a systematic study on the homoepitaxial growth of S rTiO3(001) conducted using reflection high energy electron diffraction (RHEED) and atomic force microscopy (AFM) in order to improve our und erstanding of the basic processes in the epitaxial growth of perovskit e thin films. Under certain growth conditions, the homoepitaxial growt h of SrTiO3 essentially proceeds in the layer-by-layer (2D nucleation) growth mode with the basic unit of a molecular layer. This cyclic pro cess due to unit-cell-by-unit-cell (uc-by-uc) growth is confirmed by u ndamped RHEED oscillations and the corresponding temporal evolution of AFM images of the growth front. Furthermore, the surface mobility is controlled by growth temperature and oxidation condition. By changing growth temperature or oxidation condition, crossovers from layer-by-la yer growth to step-flow like growth and from layer-by-layer growth to 3D island growth through Stranski-Krastanov growth are observed. On th e basis of these results, a universal phase diagram is proposed or the growth mode of the epitaxial film growth of complex oxides. (C) 1998 Elsevier Science B.V. All rights reserved.