Seed shape dependence of Si solid-phase epitaxy: Preferential facet growth

A new facet formation mode in Si lateral solid-phase epitaxy (L-SPE) of amorphous Si on SiO₂ is presented. This mode occurs in the case of L-SPE using a two-dimensional seed area. Depending on whether the seed shape is convex or concave, a {111} facet with a slow SPE rate or a {110} facet with a fast SPE rate dominates in the case of {100} Si substrate. This preferential facet growth is explained using a microscopic model of crystallization, and seems to be generalized to other crystal growth and etching processes. Similar results are obtained for seeds surrounded by an SiO₂ layer and for seeds surrounding an SiO₂ island. These results must be considered in practical device design.