Deposition Process of Amorphous Boron Carbide from CH[sub 4]∕BCl[sub 3]∕H[sub 2] Precursor

Amorphous boron carbide coatings have been prepared by chemical vapor deposition from CH 4 /BCl 3 /H 2 precursor mixture at low temperature ͑800-1050°C͒ and reduced pressure ͑12 kPa͒.A kinetic study has been conducted to determine the kinetic law ͑including apparent activation energy and reaction orders͒ related to the deposition within the regime controlled by the chemical reactions.On the basis of an in situ gas phase analysis by Fourier transform infrared spectrometry and a thermodynamic study of the homogeneous equilibrium, the HBCl 2 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.