Homoepitaxial growth of SrTiO3 in an ultrahigh vacuum with automatic feeding of oxygen from the substrate at temperatures as low as 370°C

Homoepitaxial growth of SrTiO3 without introducing any oxidants has been achieved at low temperatures. The growth was carried out by coevaporation of Sr and Ti metals under extremely low oxygen partial pressure (pO(2) < 1 x 10(-8) Pa). A clear reflection high-energy electron diffraction (RHEED) intensity oscillation from the layer-by-layer growth of SrTiO3 was observed during the growth at a substrate temperature of 370degreesC. The deposited film was found to have an approximately stoichiometric composition and a single-phase of SrTiO3, from the analyses of Auger electron spectroscopy (AES) and RHEED. Oxygen was automatically fed from the substrate to the growing surface. Instead, oxygen vacancies were incorporated into the bulk of the substrate. The incorporated oxygen vacancies were evaluated by positron annihilation.