Effect of Deposition Temperature on Dynamics and Mechanism of Deposition for Si-B-C Ceramic from BCla/SiCH3Cl3/H2 Precursor

The deposition rate, phase, chemical composition and microstructure of deposits were determined from 950 to 1100 ℃. With increasing temperature, the deposition rate increases, and the morphology changes from smooth to coarse, meanwhile, the concentration of silicon increases while that of boron decreases. The deposition process is controlled by chemical reactions, and the activation energy is 271 kJ/mol. At relatively lower temperature （below 1000 ℃）, the deposition process is dominated by formation of BaC. While at higher temperature （above 1000 ℃）, it is governed by formation of SiC. BaC and SiC disperse uniformly in the Si-B-C co-deposition system and form a dense network structure.