Silicon core with color
Thread Content
Hello everyone. Many people say that the colored appearance of silicon cores is due to nitrogen issues, but after testing the N2 content in H2, it was found that the level of N2 is very low； Furthermore, electron probe analysis of the colored silicon core revealed the absence of nitrogen elements. I hope everyone can give me some advice! ! !
Personally, I think it is caused by incomplete drying of the furnace barrel during cleaning.
Personally, I think it has something to do with the purity of hydrogen; improving the purity of hydrogen should lead to improvements
@On the fourth floor, oxidation rarely occurs. Moreover, after testing a large number of samples (colored surfaces) using an electron probe, Si and C elements were detected, or Si, O, and C elements. And all these colored silicon cores can be corroded by HF solution
@On the sixth floor, if it’s a problem with the purity of hydrogen, then which components in the circulating hydrogen cause abnormalities on the surface of the silicon core? Additionally, abnormal silicon cores also occur in furnaces that use pure hydrogen for growth
Start from the following aspects: use a reduction furnace, ensure that nitrogen is used to displace air with proper quality, keep the dew point below -45°C; measure this value for each furnace, record it and plot a curve, and compare it with the conditions of the colored core. (When cleaning the furnace walls, it is essential to dry and clean them thoroughly; it’s very important not to allow alkalis or other substances to remain on the furnace walls. The pressure of the automatic cleaning rotary nozzles is also crucial.) Measure the oxygen content in the gas after nitrogen displacement; record it for each batch and plot a curve, comparing it with the condition of the colored core. After nitrogen is displaced by hydrogen, the nitrogen content in hydrogen is determined using the same method. Also, avoid contaminating the silicon core. This must be drawn from a silicon core, with strict control during the processing and cleaning stages. In fact, such quality controls are no longer a challenge in the polysilicon production process. The key is the steady reduction in overall power consumption and safe operation.
Thank you so much! Additionally, I would like to ask whether the peeling of the silicon core (with a yellow-brown and black color), which mainly occurs at the root portion, could be related to the lower temperature at the root of the silicon core during feeding, resulting in amorphous silicon May I also ask what is the appropriate temperature during feeding? (We use square silicon cores.)