Thermodynamic Simulation of Polycrystalline Silicon Chemical Vapor Deposition in Si–Cl–H System
| Autor: | Gang Xie, Palghat A. Ramachandran, Zhifeng Nie, Wenhui Ma, Yongnian Dai, Yangmin Zhou, Yanqing Hou |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Silicon General Chemical Engineering 0211 other engineering and technologies Analytical chemistry chemistry.chemical_element 02 engineering and technology General Chemistry Chemical vapor deposition engineering.material Thermodynamic simulation Mole fraction Polycrystalline silicon 020401 chemical engineering chemistry Yield (chemistry) engineering Deposition (phase transition) 0204 chemical engineering Transport phenomena 021102 mining & metallurgy |
| Zdroj: | Theoretical Foundations of Chemical Engineering. 53:1048-1056 |
| ISSN: | 1608-3431 0040-5795 |
| Popis: | Based on thermodynamic data for related pure substances, the relations of (nCl/nH)Eq and (nCl/nH)o have been plotted in the Si–Cl–H system. The results show that the difference of (nSi/nCl)o and (nSi/nCl)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. |
| Databáze: | OpenAIRE |
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