Temperature distribution above a heated surface in a CVD reactor with hydrocarbon-containing gaseous mixtures

Abstract

Pyrolysis of C2H2 and CH4 gases near a heated surface was investigated using coherent anti-Stokes Raman spectroscopy (CARS). Gas temperature and hydrocarbon density spatial profiles above the surface of deposition were measured. Although the measured hydrocarbon density distribution above the surface showed a gradual decrease upon approaching the surface, the observed temperature distribution revealed the presence of a temperature maximum at distances of 300-600 mu m from the surface. The appearance of this maximum is explained by the release of condensation energy in the region where intensive homogeneous nucleation of carbon clusters takes place.