Chemical vapor deposition (CVD), the deposition of solids by chemical reaction of gaseous feed materials, is older and more complex than vacuum coating. For a long time it remained a laboratory curiosity; however, in recent years, it has become firmly established in many areas of technology, and new applications are being found.
CVD is a versatile process, yielding deposits of many metals, alloys, semimetals, oxides, carbides, nitrides, and borides, and it has several advantages, the greatest of which is superior throwing power. However, to use it effectively requires an understanding of such factors as the chemistry of the available coating reactions, the chemical and thermal stability of the substrate being coated, and the effects on mass transport of the various vapor flow patterns encountered in coating objects of simple to complex shape.
The range of applicability of CVD is discussed with examples, and guidelines are given for successful coating.