Comparison of thin-film thickness measurements using ellipsometry and reflectometry with uniform samples

This study evaluates spectroscopic ellipsometry and reflectometry using high-quality SiO 2 and Al 2 O 3 thin-films on Si substrates, thereby facilitating a detailed assessment of consistency of measurement results and uncertainty analyses. The results with detailed uncertainty budgets indicate good agreement between the two methods across a broad layer thickness range from 10 nm to 2000 nm, with deviations remaining well within the measurement uncertainties. Ellipsometry results have lower uncertainty than reflectometry results especially with the thinner layers, whereas reflectometry uncertainties are lower with the thickest layers studied. This work underscores the importance of rigorous thickness characterization and reliable uncertainty evaluation as critical factors in advancing both modeling and measurement practices in thin-film metrology.