Real-time optical monitoring of the heteroepitaxy of oxides by an oblique-incidence reflectance difference technique

Monolayer oscillations and interference oscillations were observed during the interrupted heteroepitaxy of Nb-doped strontium titanate on SrTiO3 by an oblique-incidence reflectance difference (OIRD) technique. The optical monolayer oscillations were verified by simultaneously monitored reflection high-energy electron diffraction. In modeling the surface structure as a four-layer stack, we consider the outermost incomplete layer as two parts, a homogeneous isotropic media layer with an average dielectric constant and a film layer below that with the dielectric constant of the bulk film. The numerical simulation of a simple deposition process and Monte Carlo simulation are carried out to reproduce the OIRD interference oscillations and monolayer response, respectively. The simulated amplitude of the monolayer oscillations is in good agreement with the experimental results.