Complementary analysis techniques for the morphological study of ultrathinamorphous carbon films

This article presents experimental results for morphological assessment of sub-50-nm thick hydrogenated amorphous carbon (a-C:H) overcoats. The films were grown by rf plasma enhanced chemical vapor deposition using Ar/C2H2 ga s mixture onto heterogeneous (Al2O3-TiC) ceramic substrates. They were anal yzed using complementary information from scanning electron microscopy, ene rgy dispersive x-ray analysis and atomic force microscopy. We found that th e bias deposition voltage and the nature of the substrate (Al2O3 or TiC reg ions) adversely affect both growth rate and microstructure. Argon inclusion in the C2H2 plasma during the first stage of growth is responsible for the observed effects. These results suggest that the amorphous carbon layer is denser on the TiC than on the Al2O3 region. (C) 1999 American Institute of Physics. [S0021-8979(99)00823-3].