Prediction of Elementary Reaction Mechanism for the CVD Process in Si2Cl6-H2 System using Semi-Empirical Molecular Orbital Method

Nagahiro Saito, Akio Fuwa

    Research output: Contribution to journalArticle

    Abstract

    From our previous experimental study of the Si chemical vapor deposition in Si2Cl6-H2 system, the following elementary reaction mechanism was proposed: decomposition of Si2Cl6 to produce SiCl2, which becomes the adsorbent; Si2Cl6(g) → 2SiCl3(g) → SiCl4(g) + SiCl2(g) (→ SiCl2(a)), and hydrogen reduction reaction of the absorbed SiCl2 to produce Si(s). The preliminary quantum chemistry study for this reaction mechanism has shown that the reaction is so infeasible that the above-mentioned elementary reaction mechanism is unreasonable. The most feasible and appropriate reaction mechanism has been shown as follows: (Step 1) Si2Cl6(g) → SiCl4,(g) + SiCl2(g) (Step 2) SiCl2(g) +a → SiCl2(a) (Step 3) SiCl2(a) + H2(g) → SiCl(a) + 2HCl(g) (Step 3-1) SiCl2(a) + H2(g) → Si-2HCl(a) (Step 3-2) Si-2HCl(a) → Si(a) + 2HCl(g) where, a is the active site on silicon surface. On the assumption that step 3 is the rate-determining step, this elementary reaction mechanism can explain the experimental observation in the rate expression on the concentration dependence with respect to Si2Cl6 and H2.

    Original languageEnglish
    Pages (from-to)319-325
    Number of pages7
    JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
    Volume63
    Issue number3
    Publication statusPublished - 1999

      Fingerprint

    Keywords

    • Chemical vapor deposition; CVD
    • Elementary reaction
    • Semi-empirical MO
    • SiCl

    ASJC Scopus subject areas

    • Metals and Alloys

    Cite this