STRUCTURAL CHARACTERIZATION OF AMORPHOUS SICXNY CHEMICAL-VAPOR-DEPOSITED COATINGS

Chemical bonding and local order around the different atoms of thick a morphous SiCxNy deposits [0.03 less than or equal to x/(x+y) less than or equal to 0.67] prepared with chemical vapor deposition at 1000-120 0 degrees C using TMS-NH3-H-2 have been investigated using x-ray photo electron spectroscopy (XPS), Raman spectrometry, Fourier transform inf rared spectrometry (FT-IR), electron energy loss spectroscopy (EELS) a nd Si-29 magic-angle spinning nuclear magnetic resonance spectrometry (MAS-NMR). XPS analyses have shown that the main bonds are Si-C, Si-N and C-C, and have suggested the existence of C-N bonds. According to R aman analyses and complementary FT-IR absorption of thin films, the co atings are nonhydrogenated. Si, C and N atomic chemical environments a re more complicated than in a mixture of pure Si3N4-SiC phases. The ex amination of the Si KL2,3L2,3 line shapes recorded by XPS have allowed one to state the existence of Si(C4-nNn) units. Mixed coordination sh ells around silicon have been confirmed by EELS analyses; Additionally , FT-IR reflection analyses have proved that Si is both bonded with N and C. Indirect indication has been obtained owing to the Si-29 MAS-NM R analyses of powders. Raman analyses have been conclusive to assume t hat C-C bonds correspond to a mixed sp(3)-sp(2) carbon configuration l inked with Si(C4-nNn) tetrahedra with 0 less than or equal to n less t han or equal to 4. (C) 1997 American Institute of Physics.