X-ray absorption and photoelectron spectroscopic study of plasma-nitrided SiO2 film -: art. no. 113711

Plasma-nitrided SiO2 thin film has been analyzed by synchrotron-radiation-based x-ray absorption and photoelectron spectroscopies (XAS and XPS). High-resolution N 1s XAS and N 1s, O 1s, and Si 2p XPS spectral changes were obtained for different annealing temperatures. N 1s XPS and XAS spectra show that at room temperature, besides the main species of N[Si(O-)(3-x)](3), there exist free moleculelike N-2 and HN[Si(O-)(3)](2), H2NSi(O-)(3), and N-Si2O species with surface contaminants. The spectral intensities of the N-2 and the HN[Si(O-)(3)](2), H2NSi(O-)(3), and N-Si2O species decrease as the annealing temperature increases, and finally the nitrogen exists dominantly in the form of N[Si(O)(3)](3) species above 820 K, indicating out-diffusion of molecular N-2 and structural reconstruction to form a stable structure upon annealing. The Si 2p and O 1s XPS spectra show that Si>4+ 2p peak and O 1s peak appear at 103.7 and 534.0 eV, respectively, which are higher binding energies than those of thermally grown oxynitride films with lower coverage on silicon. Upon annealing the sample, these peaks shift towards lower binding energy; similar to 0.3 eV for Si>4+ and 0.4 eV for O 1s. The causes of the peaks appearance at relatively higher binding energy and the peak shift upon annealing are discussed. (C) 2005 American Institute of Physics.