The Influence of Temperature Gradients on Partial Pressures in a Cvd Reactor

The influence of temperature gradients on the partial pressures of a binary mixture in a cold wall low pressure chemical vapor deposition reactor was determined by Raman spectroscopy of the gaseous species in the reactor. It is demonstrated for the first time that the partial pressure of the heavy constituent in the hot region of a low pressure reactor is reduced by 35 % due to the Soret effect. Model calculations that included the Soret effect are in agreement with the experimental data.