Qualitative analysis of the vapour-phase equilibrium composition in the systems Si-Cl and Si-Cl-H by matrix-isolation IR spectroscopy

Abstract

The vapour phase in the systems Si-Cl and Si-Cl-H in equilibrium with solid silicon has been analyzed quantitatively by matrix-isolation IR spectroscopy. At 1 300 K, the analysis revealed SiCl4, SiCl3 and SiCl2 in the system Si-Cl, and HCl, SiCl4, SiCl3, SiCl2, SiHCl3 and SiH2Cl2 in the system Si-Cl-H. No SiHCl, a compound which according to equilibrium calculations represents one of the dominant components, could be detected.

Reactions of SiCl2 with N2O, NO and O2

“…The two stretching modes were observed at 502 and 513 cm À1 . These same two modes have also been observed by Maass et al 20 and Leitner et al 21 in the reaction of SiCl 4 with silicon metal at high temperatures ($1300 K). Therefore, if the SiCl 2 formed in our experiment were to be deposited on the window then its bands would be clearly visible.…”

Theoretical Investigation of the Structure and Vibrational Spectrum of the Electronic Ground State X̃(1A‘) of HSiCl

“…A few years later, Conner et al doing an experiment similar to that of ref assigned emission features to monochlorosilylene (HSiCl); Ho and Breiland did the first identification of HSiCl in the spectroscopic analysis of in situ chlorosilane CVD, as well as other kinetic studies with this species . After these initial detection experiments and other in situ deposition investigations, , laboratory simulations of chlorosilane CVD, measurements using different spectroscopic techniques − and theoretical studies of chlorosilane gas-phase decomposition have been carried out. In none of the experiments was it possible to isolate HSiCl, but a series of conclusions about the existence of this biradical have been established: (a) its detection is a matter of the relative sensitivities of the detection methods, the different experimental conditions and the activation energies for the thermal decomposition pathways; (b) although SiCl 2 is a major product of the decomposition of chlorosililenes, HSiCl is also possible, which is expected to significantly affect the growth rate of the Si film; (c) mechanisms for the homogeneous gas-phase decomposition of HSiCl 3 , H 2 SiCl 2 , and H 3 SiCl in hydrogen consist of unimolecular decomposition of the chlorinated silanes and secondary chemistry due to reactions where, along with other species, HSiCl is thought to play a significant role …”