Characterization of the plasma during the growth of CNx films by RF magnetron sputtering

In this work a single Langmuir probe has been used to determine in-situ the plasma electronic temperature (T-e) and the electronic density (eta(e)) of an rf magnetron sputtering system used to grow CNx films. Sodium chloride substrates and a carbon target (99.999%) in a mixture of Ar/N-2 were used. From the voltage-current characteristics, the electronic temperature in the range of 3 to 11 eV and an electronic density in the range of 10(9) cm(-3) , depending on the pressure and the relationship Ar/N-2 in the gas mixture, were determined. These results were correlated with Fourier Transformed In frared Transmission Spectroscopy (FTIR) of the films. The stress bands in t he infrared spectra were found located at 1357, 1589 and 2247 cm(-1); these bands are related to the primary (C-N), double (C=N) and triple (C equival ent to N) bonds, respectively. On the other hand, the chemical reactions in a discharge are generated basically by electronic impacts; so, knowing the temperature and electronic density, the plasma processes can be controlled during the dim preparation to favor CNx deposition.