chemicalvapor

Chemical vapor refers to a gaseous phase containing chemical species that can participate in chemical reactions. In practice, the term is most often used in connection with processes that rely on vapors, especially chemical vapor deposition (CVD), where volatile precursors react or decompose on a substrate to form solid films. The vapor phase may include carrier gases and reactive components that influence film composition and morphology.

Vapors are generated by volatilizing liquids or solids, typically at elevated temperature, and delivered to reaction chambers under controlled pressure. The composition of the vapor stream, its temperature, and its flow rate determine reaction pathways and film quality. In CVD, precursors are chosen to provide the desired elements while minimizing unwanted byproducts; common carriers include nitrogen, argon, or hydrogen.

Applications span semiconductor device fabrication, coatings, and materials science. CVD and related gas-phase processes enable deposition of silicon nitride, silicon dioxide, polysilicon, and various nitrides and oxides, as well as carbon- and diamond-like coatings. Other related techniques include vapor-phase epitaxy and pyrolytic decomposition of volatile organometallics.

Safety and environmental considerations are important: vapors may be toxic, corrosive, flammable, or reactive. Proper engineering controls, containment, detectors, and waste treatment are essential in laboratories and manufacturing facilities.

See also chemical vapor deposition, gas-phase synthesis.