四氯化硅微波等离子氢化的新工艺
文献类型：学位论文
| 作者 | 卢振西 |
| 学位类别 | 博士 |
| 答辩日期 | 2012-06-01 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 张伟刚 |
| 关键词 | 微波 等离子 氢化 四氯化硅 温度 |
| 其他题名 | New Technology of Hydrogenation of Silicn Tetrachloride in Microwave Plasma |
| 学位专业 | 化学工程 |
| 中文摘要 | 四氯化硅氢化生产三氯氢硅，是西门子法生产太阳能级多晶硅不可或缺的关键技术之一。但传统的氢化技术——冷氢化和热氢化都存在工艺复杂、能耗高、转化率低的缺点。鉴于此，本文研究开发化学热力学非平衡的微波等离子体进行四氯化硅的氢化转化。本文通过四氯化硅氢化过程的化学热力学和复杂基元化学反应动力学计算，分析了高温氢化法难于达到高转化率的根本原因。并从理论上分析提出实现四氯化硅高转化率的条件：反应温度高于1400K，且要从反应温度以不小于1000K/s的降温速率降到900K以下。微波等离子化学的关键技术之一是设计合理的反应器。本文设计制造了一种新型的微波等离子反应器——表面波射流反应器，能够产生一种非自持的等离子体，实验结果表明这种等离子体反应器能够实现四氯化硅氢化反应的高效和高选择性转化。论文发现在氢化过程中，等离子体具有与反应化学平衡常数相关联的特征温度，在本研究中被定义为等离子的“反应活性温度”。在反应过程中，等离子体的”反应活性温度”与等离子体的气体温度以及电子温度并不相同。通过引入上述反应活性温度，建立了氢化过程中操作条件对转化率影响的数学物理模型，并以此来确定最佳操作条件。发现当SiCl4/H2摩尔比值为1，SiCl4和H2混合气体与Ar的摩尔比在1.2~1.4时，氢化反应获得最佳转化效果。同时本文还基于碰撞理论分析了微波等离子中各种粒子对四氯化硅分解的作用, 并通过实验进行验证。发现在等离子氢化反应中，决定四氯化硅转化反应进程的主要是自由电子。借助于化学热力学和反应动力学计算的结果，证明了非热力学平衡等离子体由非平衡态向平衡态转化弛豫时间宏观尺度上的瞬时性，是实现三氯氢硅高收率的主要原因。 |
| 英文摘要 | Hydrogenation of silicon tetrachloride to produce trichlorosilane is one of necessary and key technology in production of polycrystalline silicon in Siemens process. Howerver those traditional hydrogenation processes, including high-temperature hydrogen reduction and catalytic hydrogen reduction process, exhibit all of shortcomings of complicated-handling, high-energy-consumption and low-conversion-rate shortcoming etc. In view of those facts, in this study, discovery of a kind of non-thermodynamic plasma to hydronate SiCl4 was carried out. Thermodynamics and kinetics of hydrogenation of SiCl4 were calculated, which proves difficulties of high-temperature hydrogenation process gaining high-conversion ratio. The condition of high conversion was deduced, that was SiCl4 was hydronated about 1400K and the system quenched from reaction temperature to that blow 900K，and the cooling rate was 10000K/s at least. One of the most critical technologies of microwave plasma chemistry is the design of decent reactors. A new type microwave plasma reactor was developed, which was named surface wave jet reactor. It was able to produce unsteady-state plasma, and the hydrogenation of SiCl4 in the plasma could be easily handled with high conversion ratio and very high selectivity to trichlorosilane (SiHCl3). In the process of hydrogenation of SiCl4, the plasma state was found to exhibit a characteristic temperature related to the equilibrium constant, which was defined as the Reactive Temperature in the current study. The Reactive Temperature was different from the electron and gas temperatures of plasma during hydrogenation. With introduction of Reactive Temperatur, the influences of technological conditions on the conversion were investigated using a mathematic model, which was developed to determine the optimum experimental parameters. At a H2 to SiCl4 ratio of 1, with mixtures of SiCl4 and H2 to Ar ratio of 1.2 to 1.4 produced the highest hydrogenation conversion ratio. The contributions of various particles in microwave plasma on the decomposition of silicon tetrachloride (SiCl4), was evaluated according to the collision theory, and verified by a series of experiments. It was found that the high conversion of SiCl4 in this process was mainly caused by free electrons in plasma. Aid with thermodynamic and kinetic calculations, it was proved that the instantaneity of microwave plasma transition process from non-thermodynamic equilibrium state to thermodynamic equilibrium state, was the decisive factor in high yields of SiHCl3. |
| 语种 | 中文 |
| 公开日期 | 2013-09-25 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1802]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 卢振西. 四氯化硅微波等离子氢化的新工艺[D]. 中国科学院研究生院. 2012. |
入库方式： OAI收割
来源：过程工程研究所
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