Kinetics of SiO2 deposition from tetraethylorthosilicate

Article abstract of DOI:10.1149/1.2055031

The kinetics of the decomposition of tetraethylorthosilicate (TEOS) vapor to form solid SiO₂ in a well-mixed flow reactor at feed pressures from 0.001 to 0.1 Torr have been studied by monitoring reaction rates with a differentially pumped mass spectrometer to determine reactant and product partial pressures. A resistively heated molybdenum foil was used as the deposition substrate to provide surface temperatures up to at least 1300 °C. This technique provides rapid measurement (approximately 10 s) of gas composition in a well-mixed flow reactor so that reaction rates could be examined quantitatively. Changes in the partial pressures of TEOS and C₂H₄ were used to probe SiO₂ deposition kinetics. Over a wide range of temperatures and pressures, we observed +1.0 order with respect to TEOS partial pressure and an apparent activation energy of 20.9±0.5 kcal/mol. The effect of C₂H₄ partial pressure on the reaction rate was investigated by including C₂H₄ in the reactor feed. Reaction rates were found to decrease as C₂H₄ partial pressure was increased, with the order with respect to C₂H₄ varying from 0 to -2.0 as C₂H₄ pressure was increased. Also, apparent activation energies were found to increase as C₂H₄ pressures were increased. A Langmuir-Hinshelwood model incorporating product inhibition described the data very well, suggesting that the reaction product C₂H₄ adsorbs on the growing SiO₂ surface, blocking adsorption sites for TEOS. Values for model rate parameters were determined by fitting the LH model to both pressure and temperature dependences.

Full text of DOI:10.1149/1.2055031

Downloaded on 2015-01-30 to IP 147.188.128.74 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-01-30 to IP 147.188.128.74 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-01-30 to IP 147.188.128.74 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-01-30 to IP 147.188.128.74 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-01-30 to IP 147.188.128.74 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-01-30 to IP 147.188.128.74 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-01-30 to IP 147.188.128.74 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-01-30 to IP 147.188.128.74 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).