Thermodynamics of Preparing BxC Condensed Phases by CVD Using BCl3-CH4-H2 as Precursors

摘要:

采用完整热力学平衡分析验证了自愈合相BxC的产物是温度和初始气体摩尔比的函数。结果表明，凝聚相的成分与温度和气体的摩尔比（如BCl3:(BCl3+CH4) 、H2:(BCl3+CH4)）密切相关。BxC的理想沉积条件是：BCl3:(BCl3+CH4)之比为0.8，H2:(BCl3+CH4)之比在10~105.2之间，而温度应高于950 K。材料的富碳或者富硼主要通过调整BCl3:(BCl3+CH4)和H2:(BCl3+CH4)的气体摩尔比来控制

Abstract:

The products of self-healing phase BxC were examined as a function of temperature and initial gas molar ratios of BCl3:(BCl3+CH4) and H2:(BCl3+CH4) by complete thermodynamic equilibrium analysis. The results show that the composition of the condensed phase is quite sensitive to temperature and the molar ratios of BCl3:(BCl3+CH4) and H2:(BCl3+CH4). Based on our calculation, the ideal conditions for BxC deposition are as follows: the ratio of BCl3:(BCl3+CH4) is 0.8, the ratio of H2:(BCl3+CH4) ranges from 10 to 105.2, and the temperature is above 950 K. We found that the carbon-richment or boron-richment in materials are mainly adjusted by the ratios of BCl3:(BCl3+CH4) and H2:(BCl3+CH4)