Ellipsometry was used for the simultaneous analyses of
thicknesses, refractive indices (n) and extinction coefficients
(k) of all samples. All measurements were done with the angle
of incidence at 70 in the wavelength range of 300–800 nm. The choice of the angle is justified by minimum noise level. The
method of determination of physical parameters was based
on the choice of best model that enabled good fitting results
of theoretical curves of cos (D) and tan (W) to experimental
ones as a function of the wavelength (i.e. Tauc–Lourentz oscillator
model) [30]. The obtained values of thickness and optical
constants of samples are listed in Table 3.