MODEL FOR THE FORMATION OF SILICON-CARBIDE FROM THE PYROLYSIS OF DICHLORODIMETHYLSILANE IN HYDROGEN .2. SILICON-CARBIDE FORMATION FROM SILICON AND METHANE

A model is developed for the deposition of silicon carbide from the py rolysis of dichlorodimethylsilane in hydrogen, in a tubular reactor at temperatures from 700-degrees to 1100-degrees-C and 1.013 X 10(5) Pa (1 atm) pressure. Concentration of dichlorodimethylsilane varied from 2 to 8 vol%. Gas chromatography was used to determine the volatile pro ducts of reaction, and gravimetric analysis was used to determine the total silicon and silicon carbide deposition on the tube. The model de veloped based on the experimental data that assumes the following chem ical reactions: (CH3)2SiCl2 + 2H-2 --> 2CH4 + H2SiCl2 HSiCl3 + H-2 dou ble-line arrow pointing left and right H2SiCl2 + HCl H2SiCl2 double-li ne arrow pointing left and right 2HCl + Si HSiCl3 + HCl double-line ar row pointing left and right SiCl4 + H-2 Si + CH4 --> SiC + 2H-2 The ra te constants derived from a nonlinear regression analysis are reported .