The basic steps in CVD film growth are production of appropriate source gas, transport of gas to substrate, adsorption of gas on substrate, reaction on substrate and the transport of "waste" products away from substrate. The growth of films depends on all these kinetics. CVD can be carried out in a horizontal reactor as shown in Fig. 3.33. A CVD apparatus will consist of several basic components:

• Gas delivery system – For the supply of precursors to the reactor chamber
• Reactor chamber – Chamber within which deposition takes place
• Substrate loading mechanism – A system for introducing and removing substrates
• Energy source – Provide the energy/heat that is required to get the precursors to react/decompose
• Vacuum system – A system for removal of all other gaseous species other than those required for the reaction/deposition.
• Exhaust system – System for removal of volatile by-products from the reaction chamber.
• Exhaust treatment systems – In some instances, exhaust gases may not be suitable for release into the atmosphere and may require treatment or conversion to safe/harmless compounds.
• Process control equipment – Gauges, controls etc to monitor process parameters such as pressure, temperature and time. Alarms and safety devices would also be included in this category.