Si + SiH₄ reactions and implications for hot-wire CVD of a-Si:H: Computational studies

Gas phase chemistry is believed to play an important role in hot-wire CVD of amorphous silicon, serving to convert the highly-reactive atomic Si produced at the wire into a less-reactive species by reaction with ambient SiH₄. In this paper, we use quantum chemistry computations (B3LYP/cc-pvTZ) to examine the energetics and rates of possible gas-phase reactions between Si and SiH₄. The results indicate that formation of disilyne (Si₂H₂) is energetically favorable. Unlike other products of this reaction, Si₂H₂ does not require collisional stabilization, and thus this species is the most likely candidate for a benevolent precursor that participates in the growth of high-quality Si films.