Growth, microstructure and electronic properties of amorphous carbon nitride films investigated by plasma diagnostics

Amorphous nitrogenated carbon films are prepared in a dual electron cyclotr on resonance-radio frequency plasma from a mixture of methane and nitrogen gas. A marked variation of electronic properties and microstructure of the films as a function of nitrogen concentration is observed from Fourier tran sform infrared (FTIR) spectra, electron energy loss spectra, optical absorp tion spectra, x-ray photoelectron spectroscopy, ultraviolet photoelectron s pectroscopy and electrical conductivity. From the variation of intensity of different positive ions and neutral radicals, using quadrupole mass spectr oscopy and optical emission spectroscopy, the growth rate, structure and pr operties of the films are investigated. The density of methyl (CH3) radical s and the film growth rate are found to decrease with the increase of nitro gen concentration. A correlation between the C/N atomic ratio in the films and CH/CN and also CH/N ratio in the plasma is noticed. Also, the CH radica l intensity in the plasma and the amount of CH bonds in the films, observed from FTIR spectra, vary in a similar fashion as a function of nitrogen con centration. A model describing film growth and nitrogen incorporation in th e films is proposed. (C) 1999 American Institute of Physics. [S0021-8979(99 )01720-X].