Theoretical Study And Analysis Of Ellipsometer Method To Determine The Optical Film Parameters

Ellipsometry is an optical analytical technique used to determine the optical constants and the film thickness from measurements of the change in polarization state of reflecting light. It has the advantages of remarkable sensitivity, nondestructive character, and etc. However, we can not get the film parameters directly because the ellipsometr equation is a transcendental, we can not get the film parameters directly because the ellipsometer equation is a transcendental equation. We can hardly get the analytical solution for film parameters from the measured ellipsometric parametersΔandΨTherefore, to find an algorithm to inverse the measured dataΔandΨbecomes a primary but an important problem.In this dissertation we take a research of the process of spectroscopic ellipsometry data. The main task includes three parts. First, constructing a model (including structural model and optical function) of optical thin film system is discussed. According to the model calculation, we analyze the sensitivity region of ellipsometric parameters with respect to film parameters (refractive index n, extinction coefficient k and thickness d) and incident angle. Second, we introduce the simulated annealing algorithm to the data processing. And designing and writing the data processing program. Third, in this article also ellipsometer own standard thin film sample, there is no coating of glass substrate samples and plating on glass substrates at single-layer samples of TiO2 films ellipsometric parameters through simulated annealing algorithm for data processing, and good results are obtained by using the Simulated Annealing algorithm.