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Hydrogenated amorphous carbon (a-C:H) and fluorinated (a-C:H:F) thin films were deposited from acetylene/argon and acetylene/argon/sulfur hexafluoride mixtures. For the first gas mixture, the plasma was kept for 5 or 10 minutes using 9.5 Pa of pressure (30% C2H2 e 70% Ar) while for the second it was kept for 5 minutes using 30% C2H2, 65% Ar e 5% SF6 at a total pressure of 9.5 Pa. The power of the excitation signal was changed from 5 to 125 W and the effect of such parameter on the properties of the films was investigated. To fluorinate the a-C:H films they were submitted, immediately after deposition and without exposure to atmosphere, to SF6 plasma treatments. Such procedures were conducted for 5 minutes in radiofrequency (13.56 MHz, 70 W) plasmas of 13.3 Pa of pressure. Raman and X-Ray photoelectron spectroscopes were employed to investigate, respectively, the microstructure and chemical composition of the films. Film hardness and friction coefficient were determined from nanoindentation and tribometry techniques, respectively. The receptivity of the samples towards water was evaluated through contact angle data and roughness was measured by optical interferometry. The a-C:H films obtained from the C2H2 and Ar plasma mixtures in lower power (5 e 25 W) presented polymer-like structures and compositions while those prepared using intermediary power levels ( 50 e 75 W) presented higher proportions of tetrahedral carbon bonds and low proportions of hydrogen, suggesting a Diamond like Carbon (DLC) structure. Films deposited using the higher power (100 e 125 W) plasmas presented a graphitic structure. As the material prepared with lower power signals were submitted to the SF6 post deposition treatment, surface chemical composition was changed but the polymeric nature of the films was kept. The graphitic nature of the films synthesized in the higher power regime was intensified after the post deposition treatment. The films obtained from C2H2, Ar and SF6 plasma mixtures also revealed a polymeric structure as lower power were used and a graphitic for intermediary power levels (50 e 75 W). In this case, the material with the higher proportion of sp carbon-carbon bonds was that prepared with for higher power signals (100 e 125 W). Contact angle results revealed that a-C:H films deposited in different conditions are essentially hydrophilic. After SF6 plasma treatment, the films deposited in 10 minutes have their wettability altered, from hydrophilic to hydrophobic. The post deposition treatments were more effective for the fluorine incorporation and consequently to alter the film wettability than the SF6 incorporation in the deposition process. Thickness of the films deposited in 5 minutes decreased from 130 to 20 nm as excitation power was varied from 5 to 125 W. After SF6 plasma treatment film thickness was substantially reduced mainly for the 10 minutes deposited samples. This result was ascribed to the increasing effect of the ablation produced by the thermal heating during deposition and by the etchant effect of the SF6 treatment. Friction coefficient increased upon film fluorination but still good results were attained to the samples deposited for 10 minutes and to those in wich fluorine was incorporated to the depositing plasmas.

Efeito da incorporação de flúor nas propriedades de superfície de filmes DE aC:H