Optical real-time monitoring of the laser molecular-beam epitaxial growth of perovskite oxide thin films by an oblique-incidence reflectance-difference technique

Abstract

We report the results of optical in situ monitoring of the epitaxial growth of perovskite oxide thin films by an oblique-incidence reflectance-difference (OIRD) technique. Optical oscillation that corresponds to the growth cycle of an interrupted growth mode (monolayer oscillation) is observed. The monolayer oscillation shows different behaviors for layer-by-layer, Stranski–Krastanow, and three-dimensional growth modes. Optical interference oscillation is observed. The dependencies of the real and the imaginary parts of the bulk film’s refractive index on the OIRD signal are discussed and illustrated with a three-layer stack mode. Thin-film complex refractive-index and highly accurate thickness measurements can be obtained by fitting of the interference oscillation.