Silicon dioxide deposition in a microwave plasma reactor

SiO(x)C(y)H(z) films were deposited using hexamethyldisiloxane (HMDSO) in a 2.45 GHz microwave plasma reactor. The plasma was characterised by optical emission spectroscopy as a function of the HMDSO-to-oxygen ratio. The emission of species resulting from the dissociation and recombination of the monomer was identified. The film structure was investigated by means of FTIR spectroscopy and ellipsometry was used to determine the thickness and refractive index of the layer. The infrared spectrum and the deposition rate are strongly dependent on the HMDSO-to-O(2) ratio, whereas the refractive index is quite constant and lower than expected. (C) 1999 Elsevier Science S.A. All rights reserved.