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

Abstract

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.