AMORPHOUS HYDROGENATED CARBON NITRIDE FILMS OBTAINED BY PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION

Amorphous hydrogenated carbon nitride (a-CNx:H) films grown by plasma- enhanced chemical vapour deposition using methane-nitrogen mixtures as precursor gas were characterized by a combination of several techniqu es: MeV ion beam techniques (Rutherford backscattering, nuclear reacti on analysis and elastic recoil detection analysis), secondary ion mass spectrometry, Raman spectroscopy and positron annihilation spectrosco py (Doppler broadening method). The Vickers hardness and the internal stress of the films were also measured. Finally, the thermal stability of the films was investigated. Our results indicate that the incorpor ation of nitrogen into the amorphous carbon network increases the void density and the number (or size) of graphitic domains. These microstr uctural modifications and the decrease in the average coordination num ber may account for the observed reduction of the internal stress of t he films. For annealing temperatures higher than 300 degrees C we obse rve hydrogen and nitrogen losses as well as the progressive graphitiza tion of the films.