Determination of overlayer thickness by angle‐resolved XPS: A comparison of algorithms

Angle‐resolved XPS data from two well‐characterized samples of SiO 2 on Si were analyzed using three different algorithms for the determination of overlayer thickness. The relative ratio algorithm, the Heaviside step function approximation to the Laplace transform algorithm and the absolute ratio algorithm were compared in terms of the d /λ values calculated, correlated parameters, experimental requirements, goodness‐of‐fit and sensitivity to overlayer thickness variation. Although an inverse correlation exists between the normalization parameter and d /λ for the relative ratio algorithm, this algorithm is recommended over the absolute ratio algorithm and the Laplace transform algorithm for the determination of overlayer thicknesses. The relative ratio algorithm results in the most accurate overlayer thickness ratio and is more sensitive to overlayer thickness variations than the other algorithms.