Effects of atomic hydrogen on growth behavior of Si films by Si 2H 6-source molecular beam epitaxy

Abstract

The effect of hydrogen atoms on the segregation of Ge atoms has been investigated in the Si overlayer growth on Ge/Si(100) substrates by gas source molecular beam epitaxy with additional atomic hydrogen. The Ge composition on the growing surfaces decreases exponentially with increasing Si overlayer thickness. The irradiation of excess atomic hydrogen reduces the decay length of the Ge composition, which directly indicates that hydrogen atoms adsorbed on the growing surface play an important role in suppressing the surface segregation of Ge atoms. A unified linear correlation between the decay length of the Ge segregation in Si/Ge/Si(100) and the hydrogen coverage on Si atoms obtained from the Si/Si(100) homoepitaxial growth with additional atomic hydrogen has been obtained. This fact suggests that the exchange between surface Si atoms and subsurface Ge atoms is suppressed by the hydrogen atoms on surface Si atoms.