Analysis of particulates generated in a radiofrequency methane plasma by laser light scattering and optical spectroscopy

LASEP, Faculté des Sciences, Université d'Orléans, site de Bourges, rue G. Berger, B.P. 4043, 18028 Bourges Cedex, France

Corresponding author: Isabelle.Geraud@bourges.univ-orleans.fr

Received: 3 March 1999
Revised: 8 July 1999
Accepted: 27 July 1999
Published online: 15 October 1999

Abstract

The generation and the behavior of amorphous hydrogenated carbon particulates have been investigated in a pure methane low pressure radiofrequency discharge at 13.56 MHz. In the plasma, the formation and the presence of two kinds of particulates have been evidenced by use of laser light scattering. The study of the different forces acting on the particulates allowed us to understand their behavior in the discharge. Optical emission measurements have enabled us to correlate the evolutions of the emission lines (CH, H_α and H₂) with the growth of amorphous hydrogenated carbon particulates and also with the results obtained by laser light scattering. The particulate sizes have been measured and a particulate number density of about 3.0 × 10⁶ cm⁻³ has been determined.