Determination of optical functions of very thin tantalum pentoxide films on platinum substrate by genetic algorithm approach

We study the optical characteristics of tantalum pentoxide films, deposited by reactive sputtering. These films, as many other metal oxide layers, are promising candidates for optical devices in the spectral region where they have no absorption. Besides applications in modern optics, they are also investigated as high-kappa materials for the needs of nano-electronics, i.e. design of dynamic random access memories, etc. Herein, we present results on optical functions of Ta2O5 films with physical thickness of similar to 15 nm. The spectral range of evaluation covers 210-750 nm. We have estimated the Ta2O5 optical functions from spectro-photometric data. The Tauc-Lorentz-Urbach parametric model was used in the fitting procedure, which was based on the stochastic genetic algorithm.