Inductively coupled plasma and laser-induced chemical vapour deposition ofthin carbon nitride films

Thin CNx films have been deposited on silicon substrates by inductively cou pled plasma chemical vapour deposition (ICP-CVD) and by laser-induced chemi cal vapour deposition (LCVD) utilizing the focused beam of a copper bromide vapour laser. Different gas mixtures were used: CH4/N-2 and CCl4/N-2/H-2 f or ICP-CVD, and CCl4/NH3 for LCVD. Plasma properties (electron temperature, electron and ion densities, plasma potential) were studied by Langmuir pro be and optical emission spectroscopy. The growth rates ranged up to 80 nm m in(-1) for ICP-CVD and 700 mu m min(-1) for LCVD. The surface morphology wa s studied using: atomic force microscopy for ICP-CVD, and scanning electron microscopy for LCVD. Beside carbon and nitrogen, silicon and oxygen for LC VD and chlorine for ICP-CVD (in the case of the CCl4/N-2/H-2 system) was de tected by Auger electron spectroscopy. Fourier transform infrared (FTIR) sp ectroscopy was used to determine the chemical bonding structure. Bands assi gned to C=C and C=N (graphite-like domains) and to C-H bonds were detected in the films deposited by both processes. In addition, different bands attr ibuted to other types of carbon nitride bonds or to due to the presence of impurity atoms were observed in the FTIR spectra of the CNx films deposited by the ICP-CVD and LCVD. The results of both deposition techniques were co mpared and discussed on the base of the processes peculiarities. (C) 1999 E lsevier Science S.A. All rights reserved.