Structural and chemical characterization of 4.0 nm thick oxynitride films

We report x-ray reflectivity and secondary ion mass spectrometry (SIMS) analysis of several silicon oxynitride films of 4.0 nm thick as a function of nitrogen concentration at the interface between the oxide and the Si substrate. The x-ray reflectivity data have been analyzed using a model-dependent matrix method, and the results were compared with the model-independent method based on the distorted wave Born approximation and Fourier inversion refinement technique based on the Born approximation. Limitation of each of these techniques is also discussed. The x-ray reflectivity analysis of the films reveals the existence of high electron density at the region where nitrogen accumulation has been observed. Nitrogen accumulation has been observed using dual-beam time-of-flight-SIMS. The results of x-ray reflectivity have been compared with the results of SIMS. (C) 2002 American Institute of Physics.