The Bond Nature and Reactivity of Silicon Compound

Abstract

Despite of homologous elements, the bond nature and reactivity of silicon compound are different from those of carbon compound. In order to clarify the difference, theoretical studies of silane as a prototype of silicon compound were reviewed. Silane is a key compound for CVD. It has been believed that the important process of CVD is a silane decomposition reaction to form silylene (1) SiH₄ → SiH₂+H₂, followed by silylene insertion to σ bond (2) SiH₂+R-X→R-SiH₂X. There are some theoretical results for reaction (1) and (2 ), respectively. However, there has never been considered the reaction of ( 3 ) SiH₄+R-X→R-SiH₂X+H₂, as a two-step reaction composed of reaction (1 ) and ( 2 ). Therefore, our recent studies of the one-step reaction of ( 3 ) (R-X=SiH₄ NH₃ H₂O and SiH₃OH) without silylene formation were compared with those of the two-step reaction of ( 3 ). As a result, for R-X=NH₃, H₂O and SiH₃OH, the one-step reaction has an advantage over the two-step reaction under kinetic control. This may predict that there exists some milder synthetic condition of silicon compound than that of silylene formation. The specific bond nature and reactivity of silicon compound was examined by using the Bader-Pearson's perturbation theory.