Two-dimensional modelling of CH₄-H₂ radio-frequency discharges for a-C:H deposition

¹ Laboratoire de Physique des Gaz et des Plasmas, Université Paris XI, bâtiment 212, 91405 Orsay Cedex, France
² Laboratoire de Physique et Technologie des Plasmas, École Polytechnique, 91128 Palaiseau Cedex, France

Corresponding author: olivier.leroy@lpgp.u-psud.fr

Received: 12 March 2001
Revised: 11 June 2001
Accepted: 28 June 2001
Published online: 15 November 2001

Abstract

A two-dimensional numerical code, previously developed for the modelling of a-Si:H deposition in a SiH₄/H₂ radio frequency cylindrical PECVD reactor, has been modified in order to perform the modelling of CH₄/H₂ mixtures in the same experimental configuration. This model, which includes electrical and chemical modules, takes into account the transport and the chemistry of the charged and neutral species. The results of the models have been compared to measurements. The calculated electrical power coupled to the plasma and the self-bias voltages are compared to the experimental ones. The calculated radical densities are compared to those measured by threshold ionization mass spectroscopy at the substrate centre. Moreover, the calculated radial distribution of the deposition rate is compared to profilometry measurements. Eventually, results obtained here in CH₄/H₂ are compared with those previously obtained in SiH₄/H₂ plasmas under similar experimental conditions.