Critical thickness of BaTiO 3 film on SrTiO 3 (001) evaluated by reflection high-energy electron diffraction

Abstract

The critical thickness of BaTiO 3 epitaxial film growing on an atomically smooth SrTiO 3 (001) substrate is evaluated from the analysis of the Reflection High-Energy Electron Diffraction (RHEED) patterns. RHEED intensity oscillation was damped abruptly beyond the film thickness of about 10 nm. The thickness is in accordance with the theoretical critical thickness obtained using Matthews' equation, which implies that the origin of the damping of RHEED intensity oscillation is based on lattice strain relaxation. RHEED observations can directly reveal the critical thickness over which 2D–3D growth mode transition occurs during the growth.