X-ray absorption of Si–C–N thin films: A comparison between crystalline and amorphous phases

X-ray absorption near edge structure ~XANES! spectra of crystalline ~c!and amorphous (a)-Si–C–N thin films were measured at the C, N, and Si K edge using the fluorescence and sample drain current modes. A sharp peak similar to the C 1s core exciton in chemical vapor deposition diamond is observed, which can be assigned to the transition from the C 1s to sp hybridized states in c-Si–C–N. The C K edge XANES spectrum of a-Si–C–N contains a relatively large 1s →p* peak, implying that carbon atoms in the a-Si–C–N film are bonded largely in graphite-like sp configurations. A shift of the a-Si–C–N p* peak towards the lower energy by ;0.3 eV relative to that of c-Si–C–N is observed, which can be attributed to a higher degree of disorder-induced localization of excited electrons. Both aand c-Si–C–N N K-edge XANES spectra resemble that of a-Si3N4 . The Si K-edge absorption spectra of the Si–C–N thin films indicate a proportional combination of local Si–N and Si–C bonds. The increase of the binding energies of excited electrons and the broadening of the spectral features by structural disorder are also observed in the Si K-edge XANES spectrum of the a-Si–C–N film. © 1999 American Institute of Physics. @S0021-8979~99!09422-0#