DEPOSITION PROCESS OF AMORPHOUS BORON CARBIDE FROM CH_4/BCl_3/H_2 PRECURSOR

摘要

Amorphous boron carbide coatings have been prepared by CVD from CH_4/BCl_3/H_2 precursor mixture at low temperature (800-1050℃) and reduced pressure (12kPa). A kinetic study has been conducted to determine the kinetic law (including apparent activation energy and reaction orders) related to the deposition within the regime controlled by the chemical reactions. On the basis of an in-situ gas phase analysis by FTIR spectrometry and a thermodynamic study of the homogeneous equilibrium, the HBC12 species has been identified as an effective precursor of the boron element. The evidence of correlations between the various experimental approaches has supported a discussion on the chemical process involved.