Mechanisms for crystallographic orientation in the crystallization of thin silicon films from the melt

Abstract

The dependence of the growth velocity on crystal orientation has been studied during crystallization of thin polycrystalline silicon films from the melt. Two types of growth velocity anisotropy have been observed. In the first, competitive growth between (100) textured seeds and seeds with (110) and (111) textures indicates that the relative growth velocities are ν(100) > ν(110)ν(111). It is postulated that this textural growth velocity anisotropy is a result of the differences in the interal energy of grains with different textures. This assumption, combined with the data, yields estimates of the interfacial energy anisotropy for the Si–SiO2 interface: γ(111) − γ(100) = 0.069 J/m2 and γ(110) − γ(100) = 0.012 J/m2. Another type of growth velocity anisotropy is responsible for the development of in-plane orientation in competitive growth between (100)-textured seeds. Simple models, which describe development of these two types of crystallographic orientation via anisotropies in growth velocity, agree well with the experimental results.