Effect of dislocations on the shape of islands during silicon growth on the oxidized Si(111) surface

The formation of dislocation-rich and dislocation-free silicon islands during growth in the absence of mechanical stresses has been studied by scanning tunneling microscopy. The rounded shape of islands obtained at growth temperatures of $400$–$500$ $^\circ$C on the oxidized Si(111) surface is associated with the presence of dislocations within them. The transfer of atoms from the oxidized surface to the islands occurs due to the barrier of the potential energy at the SiO$_2$/Si boundary. The $\{111\}$ and $\{311\}$ facets dominate in the shape of the islands grown at $500$–$550$ $^\circ$C. Their appearance indicates the absence of the threading dislocations in the islands and that the growth is limited by the stage of the nucleation of a new atomic layer.