At room temperature, the spectroscopic ellipsometry SE parameters Epsi (ψ) and Delta (Δ) for 6H–SiC crystal substrate were measured in the wavelength range 350–1700 nm at four different angles of incidence, 60°, 65°, 70°, and 75°. An SE model was developed to extract optical consents of 6H–SiC crystal substrate from the experimentally measured SE parameters. In the wavelength range 350–1700 nm, the refractive index of the 6H–SiC crystal substrate was extracted and fitted to two terms of the Sellmeier dispersion function. In the wide spectral range (350–1700 nm), the Wemple-DiDomenico (WDD) dispersion model shows how the real refractive index changes with wavelength. The analysis of refractive index dispersion of the 6H–SiC crystal substrate using Sellmeier dispersion function and WDD optical model allows to extract oscillator strength Nfij, average oscillator energy Eo, dispersion energy of the single oscillator Ed, lattice oscillator strength El, Abbe dispersion number, energy gap Eg, density of valence electrons nv, refractive index at infinite wavelength n∞, lattice dielectric constant εL, the ratio of free carrier density to free carrier effective mass (N/m∗), and plasma frequency ωp. For the 6H–SiC crystal substrate, in the desired spectral range (240–1700 nm), it does not have any depolarization effect on the reflected polarized light.
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