Sidewall faceting and inter-facet mass transport in selectively grown epitaxial layers on SiO₂-masked Si(1 1 0) substrates

The facet formation and inter-facet mass transport in selective epitaxial growth (SEG) of Si on SiO₂-masked growth windows aligned along [1 1 0] and [1 0 0] directions on Si(1 1 0) substrates by Si gas-source molecular-beam epitaxy were studied. For the sidewalls along the [1 1 0] baseline, both (3 1 1) and (1 1 1) facets were formed, while for the sidewalls along the [1 0 0] baseline, (1 0 0) facets were formed. Mass accumulation around the edges of the top surface was shown to be due to the inter-facet mass transport from the sidewall to top surfaces.