An Ultra-fast Multiwavelength Ellipsometer with 16 different wavelengths (UMWE), was used to monitor and study: (i) the ion etching of c-Si substrate, and the subsequent formation of an amorphous Si(a-Si) overlayer and (ii) the TiNx film growth, with a Ti interlayer on Si substrate, during deposition. The ellipsometer was adapted on a high vacuum chamber system and the films were deposited with the unbalanced magnetron sputtering deposition technique. UMWE measurements were performed to study the multi-spectral response and time dependence of dielectric function epsilon(omega)(= epsilon(1) + i epsilon(2)) in the energy region 1.54-4.32 eV in terms of process parameters, ion energy (substrate bias V-b) and N-2 content in the plasma. By analysing the 'real-time' spectra we estimated the amorphization rate of Si, the thickness and the structure of alpha-Si overlayer, as well as the TiNx thickness and stoichiometry during deposition. The latter is directly related to the plasma frequency omega(p), the energy where epsilon(1)(omega(p)) = 0, that depends on V-b and N-2 content.