Plasma-Enhanced Chemical Vapor Deposition,Plasma-Enhanced Chemical Vapor Deposition,Plasma-Enhanced Chemical Vapor Deposition
PLASMA-ENHANCED CHEMICAL VAPOR DEPOSITION (PECVD), also known as plasma-assisted CVD, is an
important technique used for depositing films of a wide variety of crystalline and noncrystalline materials. Examples of films that are commonly deposited using the PECVD process are noncrystalline materials such as oxides, nitrides, and
oxynitrides of silicon (Ref 1), and crystalline materials such as polycrystalline silicon (Ref 2, 3, 4), epitaxial silicon (Ref
5, 6, 7), and refractory metals and their silicides. All of these materials are extensively used in microelectronic device
fabrication, and PECVD is a critical process step in the fabrication of modern silicon devices. PECVD is also used in
depositing optical coatings and other crystalline compounds such as titanium nitride, which is used in highly wearresistant
coatings on cutting tools (Ref 8).
Thermally driven atmospheric-pressure and low-pressure chemical vapor deposition (APCVD and LPCVD, respectively)
are well understood and established methods for depositing films in integrated circuit (IC) fabrication technology (see the
article "Chemical Vapor Deposition of Semiconductor Materials" in this Volume). However, the deposition temperatures
in a thermally driven CVD process can be quite high (e.g., 700 to 900 °C, or 1300 to 1650 °F, for LPCVD silicon nitride
deposition) (Ref 1, 9) and thus are detrimental to modern silicon devices. Plasma enhancement of the CVD process makes
it possible to lower the deposition temperature significantly (e.g., to 250 to 300 °C, or 480 to 570 °F, for PECVD of
silicon nitride) (Ref 1, 9) while maintaining a reasonable rate of deposition and film quality. Thus, some of the advantages
of PECVD are that:
· Films can be deposited on substrates that would be unstable at higher temperatures (e.g., intermetallic
dielectric layers deposited on aluminum or the encapsulation of ICs).
· Lower-temperature film deposition in microelectronic circuits allows precise control of dopant
migration. The dimensions of modern microelectronic devices are getting smaller, increasing the
importance of this control.
This article discusses application of the PECVD process in the deposition of amorphous and crystalline films from the
point of view of microelectronic device fabrication. Plasma enhancement of the CVD process is discussed briefly,
followed by a description of various types of PECVD reactors. Deposition techniques and the properties of some of the
amorphous and crystalline films deposited by the PECVD process for IC fabrication are also described.

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