Preparation and characterization of boron doped carbon thin film by low pressure chemical vapor deposition

Boron doped carbon (BC_x) thin film was prepared at 1100°C on carbon fiber substrate by low pressure chemical vapor deposition (LPCVD) from BCl₃ and C₃H₆ as boron and carbon sources respectively. Scanning electron microscopy observation results show that the BC_x coating has a smooth surface and the cross section of BC_x coating exhibits a very finely laminated structure. X-ray diffraction analysis results show that the BC_x coating consists of B₄C and pyrolytic carbon with a high degree of graphitization. X-ray photoelectron spectroscopy results show that there is 15% (in mole, the same below) boron induced in the BC_x coating. Five different chemical surroundings of boron atoms were confirmed in the BC_x coating, namely, B₄C, boron atoms substituted in the graphite-like structures, and mixtures of B-C bonding and B-O bonding referred to as BC₂O and BCO₂, B₂O₃, respectively. More than 40% of boron atoms are included by substitution in the graphitic-like structure.