Most CVD processes operate at some temperature
other than that of the ambient. Sometimes only the sample is
heated ("cold-wall reactors"); in other cases the whole
process chamber (often a quartz or glass furnace tube) is heated
to the process chamber ("hot-wall reactors"). Some
processes operate at reduced temperatures (e.g. deposition of
parylene from dimer precursors).
Changes in temperature require transport
of heat (thermal energy) from a heating element to the sample.
To control and monitor the temperature of the sample, we need
to understand the mechanisms by which heat is transported to
the sample and the methods by which temperature may be measured.
The temperature of the gas stream will be
affected by its surroundings (including heated walls or substrates),
and this temperature is in turn likely to affect the rates of
chemical reactions in the gas phase, as well as possibly changing
the nature of the fluid flow (natural convection). We need to
understand how heat is transported in the gas in order to analyze
the effects of local temperature on process behavior.
