Plasma enhanced chemical vapor deposition (PECVD)

Plasma enhanced chemical vapor deposition (PECVD) is a process used to deposit thin films from a gas state (vapor) to a solid state on a substrate. Chemical reactions are involved in the process, which occur after creation of a plasma of the reacting gases. The plasma is generally created by RF (AC) frequency or DC discharge between two electrodes, the space between which is filled with the reacting gases. Plasma deposition is often used in semiconductor manufacturing to deposit films onto wafers containing metal layers or other temperature-sensitive structures. Silicon dioxide can be deposited from dichlorosilane or silane and oxygen, typically at pressures from a few hundred milliTorr to a few Torr. Plasma-deposited silicon nitride, formed from silane and ammonia or nitrogen, is also widely used, although it is important to note that it is not possible to deposit a pure nitride in this fashion. Plasma nitrides always contain a large amount of hydrogen, which can be bonded to silicon (Si-H) or nitrogen (Si-NH); this hydrogen has an important influence on UV absorption, stability, mechanical stress, and electrical conductivity.Oxide can also be deposited from tetraethylorthosilicate (TEOS) in an oxygen or oxygen-argon plasma. These films can be contaminated with significant carbon and hydrogen as silanol, and can be unstable in air. Pressures of a few Torr and small electrode spacings, and/or dual frequency deposition, are helpful to achieve high deposition rates with good film stability.High-density plasma deposition of silicon dioxide from silane and oxygen/argon has been widely used to create a nearly hydrogen-free oxide film with good conformality over complex surfaces, the latter resulting from intense ion bombardment and consequent sputtering of the deposited molecules from vertical onto horizontal surfaces.

Further information

1. Smith, Donald (1995). Thin-Film Deposition: Principles and Practice. MacGraw-Hill
2. Lieberman and Lichtenberg (1994). Principles of Plasma Discharges and Materials Processing. Wiley
3. Dobkin and Zuraw (2003). Principles of Chemical Vapor Deposition. Kluwer
4. Article Plasma enhanced chemical vapor deposition  from Wikipedia, the Free Enciclopedia. Available under the license Creative Commons Attribution-Share Alike.

Back to Russian