Published online by Cambridge University Press: 22 February 2011
On the basis of results of surface structure analyses by reflection high-energy electron diffraction(RHEED) with dynamical calculations, adsorption processes on Si(111) surface are discussed. On adsorption processes on Si(111)7×7 surface at room temperature, adatom bonds of the dimer-adatom-stacking-fault(DAS) structure are broken by adsorbed atoms and the structure changes into other 7×7 one called δ7×7. At the transition into the δ7×7 structure the dimer-stacking-fault(DSF) frame work is preserved. From rocking curve analyses during adsorption of Li and Si, back bonds of the adatoms of ])AS structure are cut off in the initial stage of the adsorption at about 0.2 monolayer coverage of the adsorbates. Metal adsorbed δ7×7 structures axe unstable and changes into structure by heating at about 300 °C with dissolution of the stacking fault layer into the normal stacking arrangement. During homoepitaxial growth of Si on Si(111)7×7 surface at about 300 °C, a new metastable surface structure is foundby RHEEDdynamical analysis. This structure is concluded as pyramidal cluster structure formed on the DSF frame work. It is discussed that formation of metastable structure promotes transition to from the 7×7, and promotes successive epitaxial growth accompanied with stacking fault dissolution at the DSF frame work.