40 pairs of rods
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I need expert advice???????????? How can secondary feeding be controlled to prevent black flocculent substances from forming on the surface of silicon rods?
Why do some people watch but no one offers any advice? All you experts out there
First increase the temperature and let hydrogen burn without a feed, then add the feed
During the second feeding process, hydrogen should be introduced first, followed by applying current to the silicon rods for dry heating; the current level should be at least 80% of that used before shutting down the furnace. Only after that should trisilicon be added, so as to prevent the formation of amorphous silicon (i.e., the black flocculent substance you mentioned). Furthermore, this black flocculent substance is most likely the result of amorphous silicon formed when the furnace was shut down earlier, without allowing it to burn out first; power and feed were cut off immediately, and at low temperatures (due to the residual heat in the silicon rods after power was cut off), a low-temperature reaction between the remaining trisilicon substances inside the furnace took place. I mean, this post should be posted in the polysilicon section; this is the silicone section. . :L