Characterization and production metrology of gate dielectric films

We report efforts to develop optical dispersion models for new high k mater ials and silicon oxynitrides. We find the Tauc-Lorentz model provides super ior fits to Ta2O5 and ZrO2 dielectric films in the spectral range 1.5-6.0 e V. However, for typical oxynitrides which do not absorb below similar to6.0 eV, we find the Tauc-Lorentz model confers no advantage over models which do not account for absorption. For the oxynitrides, we also find a monotoni c relationship between film refractive index and nitrogen concentration, po tentially useful for gate dielectric process control. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.