I would like to ask about the issue of the beam melting
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In the later stages of polycrystalline silicon rod production using the bell jar method (such as at 140 hours and 1700+A), a temperature difference begins to appear between the upper and lower parts of the rod. This temperature difference gradually increases; the lower part melts while the upper part turns black. Over time, the rod is no longer viable for use. Why does this happen? Which parameters are related to this phenomenon? Is it the amount of gas? Temperature? The speed of increasing current? I hope for more details. I’m hoping that those who work in the field of restoration can help solve this issue
As the silicon rod grows, the temperature of the crossbeam tends to rise; in such cases, it is necessary to reduce the current to keep the temperature from getting too high
It’s growing too fast, and the frequency of current increase is too high. What are your power consumption and primary reduction rate?
I don’t know about statistical issues like power consumption and conversion efficiency
The crossbeam develops a corn-like shape; the lower part is usually in better condition while the upper part shows this effect more noticeably. As a result, no current flows through the upper part, whereas excessive current flows through the lower part, leading to melting
The crossbeam develops a corn-like shape; the lower part is usually in better condition while the upper part shows this effect more noticeably. As a result, no current flows through the upper part, whereas excessive current flows through the lower part, leading to melting. What this marine enthusiast said is incorrect – the current is the same throughout, it’s only the thickness that differs, which in turn results in different resistances and varying levels of heat generation, thereby causing melting. I asked about the reduction rate once because I think the amount of material passing through is too large, which results in a low reduction rate; moreover, excessive pressure can also cause this problem
So, to know how long the silicon rod has grown, if you’re not sure, it’s better to take a look through the viewing hole. Don’t wait until the crossbeam melts before taking action – the temperature is high at the corners of the crossbeam, which results in higher current flow, and higher current flow in turn leads to even higher temperatures
What does it mean that the material flow rate is too high? There’s too much trichlorosilane and too little hydrogen – is the ratio incorrect? ? ! ! !
It has nothing to do with the ratio; it’s still a current issue