In-situ analysis of gas phase decomposition and kinetic study during carbon deposition from mixtures of carbon tetrachloride and methane

Gas phase analyses and kinetic studies were carried out in-situ during the CVD of pyrocarbon from a methane/carbon tetrachloride mixture at low pressu re (2 kPa) and constant flow rate (50 seem). At low temperatures (<800 degr ees C), it is assumed that pyrocarbon is formed from chlorinated intermedia te species with an apparent activation energy of 180 kJ/mol. At higher temp eratures, the apparent activation energy is 140 kJ/mol and unsaturated hydr ocarbons are the most probable carbon precursors. (C) 1999 Elsevier Science Ltd. All rights reserved.