Chemical vapor deposition (CVD) is a process in which films of materials are deposited from the vapor phase by the decomposition of chemicals on the surface of a substrate. Most frequently the process is thermally driven but photo- and plasma-assisted methods are also used. The deposition of the film is controlled by a chemical reaction. Chemical vapor deposition (CVD) is a parent to a family of processes whereby a solid material is deposited from a vapor by a chemical reaction occurring on or in the vicinity of a normally heated substrate surface. The resulting solid material is in the form of a thin film, powder, or single crystal. It is a chemical process that deposits a thin-film of diverse chemical substances. A substrate is exposed to volatile precursors and react to generate required deposit. By-products emissions also generated from the process simultaneously.