EVIDENCE OF ADSORBED ATOM PAIRING DURING HOMOEPITAXIAL GROWTH OF SILICON

The early stages of silicon homoepitaxy on Si(100) are studied with low temperature scanning tunneling microscopy. Adsorbed atoms and epitaxial dimers are observed. Adsorbed atoms form previously unobserved pairs which couple via a substrate mediated interaction. Transient nonthermal atomic motion leads to the formation of atom pairs and epitaxial dimers. A paired atom acts as if constrained by a potential trough and exhibits a lower barrier to motion than an unpaired atom. Paired atoms are observed to coalesce into a normal, epitaxially oriented silicon dimer. © 1995 The American Physical Society.