Dynamic change in the surface and layer structures during epitaxial growth of Si on a Si(111)-7X7 surface

In order to investigate the dynamic process during growth of a Si layer on the Si(111)-7 X 7 surface held at 380 degrees C, the rocking curve of reflection high-energy electron diffraction (RHEED) is continuously measured at 0.5 degrees to 6 degrees at intervals of 0.05 degrees to the glancing angle of the incident electron beam which takes 18 sec. At the initial growth stage, the multilayer islands are grown on the native 7 X 7 surface with broader Bragg peaks in the rocking curve than those from the native surface. The sharpness of the Bragg peak is subsequently recovered after the thickness of the Si layer reaches 3 BL (1 BL = 0.31 nm), at which the growth transforms to layer-by-layer growth. The comparison of the measured rocking curve with the calculated one based on the dynamical theory of RHEED intensity is also performed by optimizing each atomic position in the growing layer so as to minimize the difference between both curves. The space of the double layer of the (111) plane in the multilayer islands expands and is restored to the normal spacing after the growth mode transforms to the layer-by-layer mode. The broadening of the Bragg peaks at the initial growth stage relates to the rearrangement process of a stacking-fault layer in the 7 X 7 structure on the substrate surface.