ELECTRONIC AND ATOMIC STRUCTURES OF THE SI-C-N THIN-FILM BY X-RAY-ABSORPTION SPECTROSCOPY AND THEORETICAL CALCULATIONS

This study measures the x-ray-absorption spectra of a crystalline (c)- Si-C-N thin film at the C and Si K edge using the sample drain current mode and at the N K edge using the fluorescence mode. A resonance pea k resembling the C Is core exciton in the chemical-vapor-deposition-di amond/Si is observed. In addition, a broad feature is round in the ene rgy range between similar to 290 and 305 eV, which can be assigned to the antibonding C 2p-Si 3sp hybridized states and the C 2p-N 2sp hybri dized states as well. The fact that the resonance peak is located simi lar to 1.5 eV below the C Is ionization energy suggests that the Frenk el-type exciton model can appropriately describe the core exciton of c arbon atoms in c-Si-C-N. Closely examining the N K edge near edge abso rption Spectra reveals similar features in both c-Si-C-N and alpha-Si3 N4, indicating that nitrogen atoms generally have a similar local envi ronment in these two materials. Moreover, results obtained from Si K-e dge absorption spectra of c-Si-C-N demonstrate a proportional combinat ion of local Si-N and Si-C bonds associated with the local tetrahedral C-Si-N-3 arrangement as well as the long-range ordered atomic structu re around Si atoms. Theoretical calculations using the first-principle s pseudofunction method are also presented and compared with experimen tal data. [S0163-1829(98)08037-0].