MICRORAMAN AND MICROHARDNESS STUDY OF NITROGEN-IMPLANTED DIAMOND-LIKECARBON-FILMS

Amorphous carbon films grown by PE-chemical vapour deposition have bee n implanted with nitrogen ions at room temperature, with an energy of 150 keV and doses up to 1 x 10(17) cm(-2). After implantation, the imp lanted region of the layers show structural inhomogeneities with sizes of approximately 100 mu m. The different regions in the layers (impla nted and not implanted) have been analysed by Raman scattering and Mic rohardness measurements. The results obtained show that the film hardn ess in the inhomogeneous region exceeds approximately five times the h ardness of the implanted region without inhomogeneities. This effect i s related to the ion beam induced compaction of the film and to a stru ctural transformation in the inhomogeneous region, as suggested by Mic roRaman measurements. The appearance of the inhomogeneities with the i mplantation is likely to be related to the existence of local mechanic al strains in the film. (C) 1998 Elsevier Science Ltd. All rights rese rved.