Modification of the surface morphology of silicon(111) with growth temperature

Silicon epitaxy has been performed on nominally on-axis silicon(111) substrates by reduced pressure chemical vapour deposition at a variety of temperatures, keeping a constant deposited thickness. Atomic force microscopy of the resulting growth surfaces shows well defined step edges, and a clear modification of the surface morphology from smooth terraces to triangular island structures as the growth temperature is reduced. The radius of curvature of these growth forms links the diffusion distance to an Arrhenius plot, with a value of EA > 400 kJ/mol, which is nearly double the energy of a silicon–silicon bond (226 kJ/mol). This implies that the silicon atoms are held on the two dimensional surface by more than just a single SiSi bond. In addition, small residual islands on the smooth terraces have a similar density to that seen in similar growth studies on silicon(100).