Is the chemical reaction in the reduction furnace mainly a decomposition reaction or a reduction reaction?
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There are as many as 15 reactions taking place in the reduction furnace, but the main reaction mentioned in general literature is SiHC13 + H2 → Si + 3HCl – Q. In reality, however, the decomposition reaction 4SiHC13 → Si + 3SiC14 + 2H2 is also quite significant. How can the progression of this decomposition reaction be controlled during the adjustment process?
Mainly the reaction temperature, mixture ratio, and air intake flow rate
It’s probably related to the reaction conditions
The key factor is the ratio of hydrogen to TCS; the temperature is usually similar in both cases
Chemical reactions are inherently very complex processes; as long as the conditions are well controlled and a high yield is achieved, it will meet our requirements.
Isn’t it said that producing one ton of polysilicon generates over ten tons of silicon tetrachloride? Therefore, reduction should primarily involve thermal decomposition. Additionally, according to the first reaction equation, silicon and hydrogen chloride are produced; during the reduction process, hydrogen levels increase, so thermal decomposition is the main mechanism at play
Both decomposition reactions and reduction reactions are taking place; the decomposition reaction occurs more rapidly, while the reduction reaction is slower.
This requires lengthy statistical analysis, with many variables such as different silane-to-hydrogen ratios, different feed compositions, different rod diameters, different currents, and different flow rates.
The temperature inside the furnace is too high, so it can only be analyzed from the exhaust gases.
In current processes, thermal decomposition reactions generally play a dominant role