X-ray absorption near-edge structure and optical properties of hafnium oxynitride thin films

Abstract

Using the suggested local structures of HfO2 (coordination number: 7.0), Hf4O5N2 (6.25), and Hf4O2N4 (5.5) in the previous research, we analyzed the effects of film composition on the X-ray absorption near-edge structure (XANES) spectra for O K-edge and N K-edge of hafnium oxynitride (Hf-O-N) thin films. The dispersion of optical constants for Hf-O-N thin films was analyzed using a four-phase model of ambient/graded/film/substrate for spectroscopy ellipsometry analysis. Two Cody-Lorentz models were applied for the spectroscopy ellipsometry analysis of films based on the XANES spectra. The effects of film composition on the dispersion of optical constants and on the surface degradation were analyzed.