Chemical Vapour Deposition is the reaction of gaseous products on the surfaces of a substrate to a solid layer. The reaction is usually started by high temperature what requires high temperature of the substrate. The thermal stability of many substrates is not sufficient to execute this process.
However several variations of the process have been developped.
Most essentially it must be differentiated between thermal CVD processes and Plasma activated CVD processes.
Thermal CVD processes are chemosynthesis, pyrolysis and disproportioning.
In the Plasma Activated CVD process (PACVD, PECVD) the chemical reaction is activated by plasma reactions.