Surface Reconstructions Of Si(001) Observed Using Reflection-High-Energy-Electron Diffraction During Molecular-Beam Epitaxial-Growth From Disilane

The growth of Si(001) from a gas source molecular-beam epitaxy system (Si-GSMBE) using disilane (Si2H6) was investigated. The surface reconstructions occurring between 100-775-degrees-C were studied as a function of both substrate temperature and surface coverage. Further, we report the first observation of (2 X 2) and c(4 X 4) reconstructions during growth at substrate temperatures near 645-degrees-C using Si2H6. All growth was found to be initiated by the formation of 3D islands which coalesce at substrate temperatures above 600-degrees-C, following which, growth proceeds in a two-dimensional (2D) fashion. The Si surface was found to have undergone a series of reconstructions which were related to the number of hydrogen adatoms and Si dimers covering the surface.