Effect of hydrogen on the structure of Si and C clusters formed in gas phase by CVD processes

摘要

Hartree Fock (HF) method and the hybrid density functional theory have been used to find the structure of Si and C clusters that are created in gas phase by Chemical Vapour Deposition (CVD). The role of hydrogen in analysed system has been examined. The results indicate that the presence of hydrogen in the CVD processes strongly affects the structure of Si, C compounds which are formed in gas phase. It has been shown that structures with high hydrogen coverage are energetically favourable Conducting process in H_2 ambient is considered to stabilise sp~3 structure. The presence of hydrogen enhances the creation of tetrahedral Si and C clusters that are supposed to be crystal nuclei. The adsorption of gaseous SiH_3 and CH_3 species on silicon and carbon surface has been analysed. The reaction between gaseous species and third-order surface atoms seems to be favourable.