RHEED intensity oscillations for the stoichiometric growth of SrTiO{sub}3 thin films by reactive molecular beam epitaxy

摘要

The growth of high quality multicomponent oxide thin films by reactive molecular beam epitaxy (MBE) requires precise composition control. We report the use of/u situ reflection high-energy electron diffraction (RHEED) for the Stoichiometric deposition of SrTiO{sub}3 (100) from independent strontium and titanium sources. By monitoring changes in the RHEED intensity oscillations as monolayer doses of strontium and titanium are sequentially deposited, the Sr:Ti ratio can be adjusted to within 1% of stoichiometry. Furthermore, the presence of a beat frequency in the intensity oscillation envelope allows the adjustment of the strontium and titanium fluxes so that a full monolayer of coverage is obtained with each shuttered dose of strontium or titanium. RHEED oscillations have also been employed to determine the doping concentration in barium- and lanthanum-doped SrTiO{sub}3 films.