Improvement of Reflectance Spectroscopy for Oxide Layers on 4H-SiC

In this work, we investigate the use of reflectance spectroscopy as an accurate, fast, and non-destructive method for measuring the thickness of transparent layers, such as SiO2, with thicknesses below 200 nm for microelectronic applications. To this end, we fabricated different oxides and analyzed their reflectance spectra using reflectance spectroscopy. The results were compared to theoretical reflectance spectra to validate the method. We introduce key factors to ensure accurate measurement by modeling the reflectance spectra of thin oxide layers with thicknesses ≥ 15 nm on 4H-SiC using the transfer matrix method (TMM).