Influence of precursor gases on the structure of plasma deposited amorphous hydrogenated carbon–nitrogen films

The atomic structure of amorphous hydrogenated carbon–nitrogen films was studied by electron energy loss spectroscopy (EELS). The films were deposited onto Si(100) substrates by rf plasma decomposition of CH4–NH3 and CH4–N2 mixtures, with substrates placed on the powered electrode of a diode glow-discharge system. The sp2 fraction of C and N atoms as a function of the nitrogen content in the films was obtained by EELS analysis. An increase of the carbon sp2 fraction with increasing fraction of NH3 and N2 feed gases was observed. The variation in the atomic structure of the a-C(N):H thin films is correlated to the internal compressive stress.