Control of growth mode in SrTiO3 homoepitaxy under 500°C

Homoepitaxial SrTiO3 thin films were grown by laser molecular beam epitaxy. The growth mode was determined by in-situ reflective high energy electron diffraction, and the surface of the films was studied by ex-situ atomic force microscopy. At the deposition rate of 0.16Å∕sec and the laser energy density of 6J∕cm2, layer-by-layer growth was observed above 460°C substrate temperature, while the Stranski-Krastanov growth mode, that is layer-by-layer growth plus island growth mode, prevailed between 460°C and 410°C. On further decreasing the substrate temperature, the island growth was determined under 410°C. With the optimization of deposition process in terms of laser energy density and deposition rate, the lowest crystallization temperatures of SrTiO3 films grown in layer-by-layer growth mode were obtained as low as 280°C. The effects of laser energy density on growth temperature were studied.