Bonding properties and their relation to residual stress and refractive index of amorphous Ta(N,O) films investigated by x-ray absorption spectroscopy

Abstract

This work presents N, O K-edge x-ray absorption near-edge structure (XANES) and Ta L3-edge extended x-ray absorption fine structure (EXAFS) studies of amorphous Ta(N,O) films prepared with various flow rate ratios of N2∕O2. The N and O K-edge XANES and Ta L3-edge EXAFS spectra demonstrate the presence of N2 molecules. These spectra also show that Ta(N,O) films have similar local atomic structure as that of Ta2O5. No evidence of the formation of Ta–N bond was obtained. The intensities of the π* feature in the N K-edge spectra and the features of O2p–Ta5d hybridized states were found to correlate with the residual stress and the refractive index, respectively.