Experimential observation of SiO2 precipitation reaction on a Si substrate through thermal decomposition of TEOS was pursued as functions of temperature, TEOS concentration and residence time where the gaseous reaction products identified by the atmospheric mass-spectrometer are C2H5 and C2H5OH, from which the following reaction scheme can be proposed: (1) The overall thermal decomposition reaction of TEOS to precipitate SiO2(s) can be expressed as follows: SiO (OC2H5)4(g) → SiO2(s) +2C2H4(g) +2C2H5OH (g) (2) The gaseous reaction intermediate species observed is SiO (OC2H5)2, which may be produced by the following reaction: Si (OC2H5)4(g) → SiO(OC2H5)2(g) +C2H4(g) +C2H5OH(g) (3) The oder of reaction with respect to the TEOS concentration obtained experimentally is from 0.2 to 0.5. (4) The above-mentioned experimental observation, in which the step (c) is the rate controlling step and the oder of reaction is (1/3), leads to (a) the thermal decomposition of TEOS to produce the intermediate: Si(OC2H5)4(g) → SiO (OC2H5)2(g) +C2H4(g) + C2H5OH(g) (b) the adsorption reaction of the intermediate: SiO(OC2H5)2(g) + * → SiO(OC2H5) * (c) the SiO2(s) precipitation from the adsorpted speciees: SiO(OC2H5)2*→SiO2(s) +C2H4(g) +C2H5OH(g).
|ジャーナル||Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals|
|出版ステータス||Published - 1996|
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