Atomic Layer-by-Layer Growth of Homo-epitaxial SrTiO$_{3}$ Films by Laser MBE

A precise customization of oxide hetero-structures at the atomic layer level became possible with layer-by-layer growth of oxide thin films by laser MBE from separate oxide targets. In situ characterization during growth helps to optimize the composition of these superlattices. In this work we focused on the reflection high energy electron diffraction (RHEED) spot analysis for in situ growth control of stoichiometric SrTiO$_{3}$ thin films in an atomic layer-by-layer manner from separate SrO and TiO$_{2}$ targets. We have shown that both stoichiometry and full monolayer dose can be controlled using RHEED diffraction spot intensity oscillations. Observations of a single sharp peak in x-ray diffraction spectra confirm the same composition of the films as that of the stoichiometric SrTiO$_{3}$ substrate. We have successfully demonstrated that this new approach of laser MBE can achieve the same precise stoichiometry control as shown by reactive MBE.