RHEED intensity oscillation during epitaxial growth of Ag on Si(111) surfaces at low temperature

Epitaxial growth of Ag onto the Si(111) surface was studied using reflection high-energy electron diffraction. To understand the mechanism of epitaxy, its dependence on the substrate temperature and deposition rate was systematically investigated. The change in the intensity oscillations when the temperature is decreased from room temperature to 160 K was seen to be identical to intensity oscillation changes observed while increasing the deposition rate from 4.02 to 60 ML/min holding substrate temperature constant. The intensity oscillations are irregular up to 6 ML and become regular above 6 ML. The regular period after the growth of 6 ML is smaller than the thickness of the Ag(111) layer. A model for Ag growth on the Si(111)-7×{}7 surface at 160 K is proposed. The changes in periodicity are attributed to island and defect formation.