IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Plasma Science Tuesday Sessions
       Session PS2+TF+SE-TuA

Invited Paper PS2+TF+SE-TuA1
Mechanisms Involved in the PECVD of Thin Films in Low Pressure Organosilicon Plasmas

Tuesday, October 30, 2001, 2:00 pm, Room 104

Session: PECVD/IPVD
Presenter: A. Granier, Institut des Matériaux Jean Rouxel, France
Authors: A. Granier, Institut des Matériaux Jean Rouxel, France
A. Goullet, Institut des Matériaux Jean Rouxel, France
K Aumaille, Institut des Matériaux Jean Rouxel, France
G. Borvon, Institut des Matériaux Jean Rouxel, France
C. Vallee, LEMD, France
G. Turban, Institut des Matériaux Jean Rouxel, France
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Low pressure organosilicon plasmas are widely used for the deposition of thin organic and inorganic films, used for their dielectric, optical and barrier properties. The organosilicon precursors such as tetraethoxysilane (TEOS), hexamethyldisiloxane (HMDSO) or tetramethylsilane (TMS) are used either pure or mixed with Ar, He, O@sub 2@ or N@sub 2@. The subject of this talk is to present the state of knowledge on the mechanisms involved in the low pressure (1 to 50 mTorr) organosilicon plasmas namely, both homogeneous and heterogeneous reactions. Since the data related to organosilicon reactions are relatively poor, information has to be deduced from experiments. Systematic plasma analyses have been carried out in low pressure RF inductively coupled TEOS and HMDSO based plasma by optical emission spectroscopy, Langmuir probes and mass spectrometry coupled with real time monitoring of the film growth by ellipsometry. It is deduced that electrons are more efficient than O atoms to break HMDSO and TEOS molecules. Organosilicon dissociation rates higher than 90% are easily reached. It is likely that the by-products of the electron impact dissociation are light H and CH@sub 3@ radicals and big fragments directly issued from the organosilicon molecule. On the other hand, in order to get better insight in heterogeneous reactions with O, H atoms, organosilicon film have been exposed to pure Ar, oxygen and hydrogen plasmas. It is demonstrated that oxygen atoms are very efficient to oxidize the organic part of the films, and that a 50 nm thick organosilicon film can be totally transformed into a porous silica film, upon exposition to an oxygen plasma.