K. Aumaille et al., Mass spectrometric investigation of the positive ions formed in low-pressure oxygen/tetraethoxysilane and argon/tetraethoxysilane plasmas, J APPL PHYS, 89(9), 2001, pp. 5227-5229
In this article, we report results on mass spectrometric investigation of t
he positive ions created in a low-pressure radio frequency helicon plasma r
eactor using oxygen/tetraethoxysilane (O-2/TEOS) and argon/tetraethoxysilan
e (Ar/TEOS) mixtures. It is shown that the variety of ions is much greater
in the Ar/TEOS plasma than in the O-2/TEOS plasma. In the case of the Ar/TE
OS plasma, ions are observed up to 343 amu whereas in the case of the O-2/T
EOS plasma, ions are observed up to 211 amu. Ion/molecule reaction rates be
tween TEOS parent positive ions and neutral TEOS molecules are considerably
less important in the O-2/TEOS plasma as compared with the Ar/TEOS plasma.
Using the values of the TEOS dissociation degree measured for O-2/TEOS and
Ar/TEOS plasmas, the observed ion/molecule reactions might be explained by
the higher concentration of TEOS molecules in the Ar/TEOS plasma.