Abstract—

Based on thermodynamic data for related pure substances, the relations of (n_Cl/n_H)_Eq and (n_Cl/n_H)_o have been plotted in the Si–Cl–H system. The results show that the difference of (n_Si/n_Cl)_o and (n_Si/n_Cl)_Eq is the driving force for polycrystalline silicon chemical vapor deposition (CVD). SiHCl₃ is preferred for polycrystalline silicon deposition to SiCl₄. SiH₂Cl₂ would be even better, but it is not stable as a gas and hence it is less frequently used. Then, thermodynamic simulation of polycrystalline silicon CVD in the Si–H–Cl system has been investigated. The pressure has a negative effect on polycrystalline silicon yield. The optimum temperature is 1400 K, at which the kinetic rate of rate-determining step for the main reaction is large enough. The excess hydrogen is necessary for polycrystalline silicon CVD in the Si–Cl–H system. However, the silicon deposition rate increases then decreases with increasing H₂ molar fraction. The optimum H₂ molar fraction should be determined by considering thermodynamics and transport phenomena simultaneously. Finally, the optimum conditions have been obtained as 1400 K, about 0.1 MPa, and H₂ to SiHCl₃ ratio of 15, which are close to the limited reported values in the open literature. Under the optimum conditions, the silicon yield ratio is 34.82% against 20% reported in the open literature.

中文翻译：

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Si–Cl–H系统中多晶硅化学气相沉积的热力学模拟

摘要-

根据有关纯物质的热力学数据，在Si–Cl–H系统中绘制了（n _Cl / n _H）_Eq和（n _Cl / n _H）_o的关系。结果表明，（n _Si / n _Cl）_o和（n _Si / n _Cl）_Eq之差是多晶硅化学气相沉积（CVD）的驱动力。对于将多晶硅沉积到SiCl _4而言，优选使用SiHCl ₃。SiH ₂Cl ₂会更好，但它作为气体不稳定，因此使用频率较低。然后，研究了在Si–H–Cl系统中多晶硅CVD的热力学模拟。压力对多晶硅产率有负面影响。最佳温度为1400 K，在该温度下，主反应速率确定步骤的动力学速率足够大。对于Si–Cl–H系统中的多晶硅CVD，多余的氢是必需的。然而，随着H ₂摩尔分数的增加，硅沉积速率先增加然后降低。最佳H ₂摩尔分数应通过同时考虑热力学和传输现象来确定。最终，获得了最佳条件，即1400 K，约0.1 MPa，H ₂与SiHCl _3的比率为15，这接近公开文献中有限的报道值。在最佳条件下，硅的产率为34.82％，而公开文献中报道的为20％。