Solid-phase growth of large aligned grains during scanned laser crystallization of amorphous Ge films on fused silica

Abstract

Well-aligned grains of dimensions up to 2–3×100 μm have been obtained by laser crystallization of amorphous Ge films on fused-silica substrates. A theoretical model has been developed for the dynamics of the crystallization process, a solid-phase transformation that is greatly accelerated by liberation of the latent heat of transformation, resulting in either periodic or runaway motion of the crystallization front. We believe that scanning of amorphous films with an energy beam of large aspect ratio may be developed into an effective process for preparing large-grained or even single-crystal sheets of Ge and other semiconductors, including Si and GaAs.