INFLUENCE OF BORON ADSORPTION OVER SI(111) SURFACE ON SI MOLECULAR-BEAM EPITAXIAL-GROWTH STUDIES BY REFLECTION HIGH-ENERGY ELECTRON-DIFFRACTION

Epitaxial growth of Si on top of a boron-adsorbed Si(111) surface was studied in molecular beam epitaxy (MBE) system. When the initial boron coverage was more than 1/3 monolayer (ML), reflection high-energy electron diffraction (RHEED) intensity oscillation showed a 4 ML period in the early stage of Si growth as long as surface-segregated boron at the growing surface was more than 1/3 ML, and turned to the normal 2 ML period of oscillation. Periodical change of the full width at half-maximum (FWHM) of the RHEED specular spot confirmed that this is due to two-dimensional island growth of 4 ML height and the coalescence mode of Si.