The growth rate of film is proportional to F and there are rate-limiting cases. In the case of small h_G, it is mass transfer limited and growth controlled by transfer to substrate; h_G is not very temperature dependent the common limit is at higher temperatures. For small k_S, it is surface reaction limited and the growth controlled by processes on surface like adsorption, decomposition, surface migration, chemical reaction, desorption of products. The k_S is highly temperature dependent (increases with T), common limit at lower temperatures. This is often preferred scheme.

The gas sources are thermally, optically, or electrically (plasma) reacted with a surface. There are four different types of CVDs are popular; Atmospheric Pressure CVD (APCVD), Low Pressure CVD (LPCVD at ~0.2 to 20 torr), Metal Organic CVD (MOCVD) and Plasma Enhance CVD where plasmas are used to force reactions that would not be possible at low temperature.