The plumbing on the oxidation furnace allows you to switch between a flow of dry O2, or to route
it through a container of boiling H20.
O2 passing over boiling water becomes saturated
with water vapor and this promotes faster growth of SiO2. This "wet" or "steam"
oxide is thus used where thicker oxide layers are required. On the other hand, oxides grown with simple
O2 are of a higher electrical quality and must be used in the "gate" electrodes of transistors.
