Black spots on silicon rods
Thread Content
During the growth of silicon rods, black spots may suddenly appear over large areas on their surface. Is this caused by the liquid material or by some dirt?
This is caused by atomization; the amorphous silicon that is formed deposits on the silicon rod. Shut down the furnace – if it doesn’t stop, layers will form
I don’t think it’s for the reasons mentioned above; it’s because it has been nitrided.
N turns yellow or light yellow; if this happens suddenly and in large amounts, it’s likely that some dirt has gotten inside. If amorphous silicon is formed merely due to insufficient temperature control, this process is very slow
If liquid enters suddenly, this process is also very fast
Reply to 5# oscar~ Agree, it’s probably because the mixture hasn’t fully vaporized
Personally, I think it’s either a sudden decrease in trichlorosilane in the mixture or an excess of silicon powder in the chassis.