Is it true that there is no deposition on hot walled tubes? That doesn't sound right. Poly, nitride, all these materials deposit on the inside of the LPCVD tubes, don't they? Perhaps hot wall and cold wall are switched in the Method of Operation section.
Topic on Talk:Low pressure chemical vapor deposition
question about hot walled
I think you typically have less deposition on hotter surfaces (at least this is how all of my tools work...), it's more likely to "precipitate"/"condense" onto cooler surfaces. But probably someone with more experience with deposition should comment :)