Determination of Rate Controlling Step in CVD Processes with Gas Phase and Surface Reactions

Abstract

An analytical model incorporating the individual effects of gas phase and surface reactions in CVD processes is presented. It is shown that the rate controlling step in the CVD process can be determined from the trends exhibited by the deposition rate profiles. This is an important step in the optimization scheme to obtain the most uniform deposition profile. The results are first derived for a highly idealised simple CVD process with a single gas phase reaction and a single surface reaction. It is shown that despite these assumptions, the predictions work well for real CVD system such as pyrolysis of tetraethoxysilane.