Color Dependency on Optical and Electronic Properties of TiN_x Thin Films

摘要

In-situ and real-time Spectroscopic Ellipsometry (SE) has been employed for the investigation of the correlation between visual appearance and optical and electronic properties of TiN_x nanocrystalline coatings. These films were deposited onto c-Si substrates by Reactive Magnetron Sputtering in an unbalanced configuration. It has been found that the N₂ content in the gas discharge, which controls the nitrogen composition in the film, plays a major role in the color control for TiN_x films. The effect of the nitrogen amount on the color of the TiN_x thin films has been investigated by the analysis of the measured pseudo-dielectric function . We also present a comparison between the electronic properties of these films and TiN_x coatings fabricated with Balanced Magnetron Sputtering in similar deposition conditions. Insights on the optical and electronic properties were arisen from the analysis of SE spectra, using the combined Drude-Lorentz model, which describes the optical response of the conduction and valence electrons. The energy, strength and broadening of the interband transitions as well as intraband absorption provided by the conduction electron density were studied with respect to the applied bias voltage, V_b.