Authors: T Belmonte G Henrion T Gries
Publish Date: 2011/03/24
Volume: 20, Issue: 4, Pages: 744-
Abstract
This study is a review of plasma enhanced chemical vapor deposition PECVD at atmospheric pressure Sources for coatings over large area are presented Millimetric torches and microplasmas are next studied for localized PECVD A specific attention is paid to the way power is dissipated and the consequences it has on the deposition rate and on quality of thin filmsThermally assisted deposition at atmospheric pressure has been studied intensively during the 1970s and 1980s where there was an urgent need to deposit episilicon Ref 17 Many basic works Ref 813 showed the importance of controlling the gas hydrodynamics whose complexity especially in terms of instability Ref 12 13 required strong numerical efforts to be accurately described by computational fluid dynamics Special efforts were also carried out to determine the reaction mechanisms at the origin of thin film deposition Ref 1416Resorting to nonequilibrium media like those commonly produced by plasma assistance offers several advantages among which one finds two important features first the possibility to deposit thin films down to room temperature Ref 17 second—and this aspect has recently been emphasized Ref 1821—the possibility to nanostructure surfaces by submitting a surface to extremely nonequilibrium media What is meant here by “extremely” nonequilibrium is a huge difference in the characteristic plasma temperatures and steep gradients in temperature and density This scope has been found out only recently likely because remote plasmas rather than direct plasma processes have been more specifically studied Ref 2226 The spatial separation between the discharge generation region and the deposition area thus reducing the possibility of bombardment of the growing film by plasma species provides a better control of the layer growth Ref 27 Generally the less stable compounds are introduced downstream from the discharge what simplifies considerably the chemical pathways leading to less interdependence of process parameters Ref 22
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