Reflection High-Energy Electron Diffraction Intensity Monitored Homoepitaxial Growth of Srtio3 Buffer Layer by Pulsed Laser Deposition
Abstract
Reflection high-energy electron diffraction (RHEED) has been used to monitor the homoepitaxial growth of SrTiO3 on (001) SrTiO3 by pulsed laser deposition. The RHEED pattern becomes sharp and streaky after deposition, indicating that the smoothness of the SrTiO3 substrate surface is improved by the growth of the buffer layer. High-resolution electron microscopy confirms that the growth of the buffer layer provides a very smooth surface with unit-cell roughness. On a smooth surface, the growth of SrTiO3 occurs in a layer-by-layer mode, as indicated by the damped intensity oscillations of the specular spot in the RHEED pattern. By interrupting the growth the specular beam recovers in intensity, and the oscillations are re-initiated with subsequent growth. Persistent RHEED oscillations, which reach an undamped steady state with superimposed beats, are observed when using a rastered laser beam for deposition. The above results suggest that that pulsed laser deposition is a useful technique for in situ growth of a smooth SrTiO3 buffer layer, which is important for the quality of the film subsequently deposited. © 1993, American Vacuum Society. All rights reserved.