Interface structures during solid-phase-epitaxial growth in ion implanted semiconductors and a crystallization model

Abstract

We have investigated the interface structures during solid-phase-epitaxial (SPE) growth in ion implanted silicon and gallium arsenide using high-resolution, cross-section electron microscopy. The crystalline amorphous (c-a) interface during solid-phase-epitaxial growth on {001} faces in silicon was found to be planar with undulations of ∼5 Å over 200–500 Å intervals. However, above certain dopant concentrations that were much higher than the solubility limits, the SPE growth was completely halted, and the c-a interface was observed to become unstable by developing large undulations that resulted in the formation of twins. The solid-phase-epitaxial growth on {111} faces in Si contained atomically smooth interfaces at first. This was followed by the formation of twins. However, the growth on {001} faces of GaAs was found always to be accompanied by the formation of twins. A model of crystal growth in diamond cubic lattices is presented, which can account for the orientation dependence of SPE growth rates, the nature of interfacial instability, and the formation of twins during SPE growth in Si and GaAs.