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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Numerical Study of the Effects of Surface Micro-roughness on the Optical Constants of Aluminum Determined by Spectroscopic Ellipsometry

Get access (open in a dialog) DOI: 10.1615/IHTC15.rad.009382
pages 7087-7094

Sinopsis

Optical Constants are the fundamental thermophysical properties of materials, and spectroscopic ellipsometry (SE) has been widely applied to measure the optical constants of solids. During the ellipsometric measurements, the surface micro-roughness is one key issue, which will induce some derivation of the optical constants from the true values. The roughness layer (RL) model based on the effective medium approximation has been routinely employed to consider the effects of the surface micro-roughness, yet the accuracy of the RL model remains unverified. In this work, the SE parameters of aluminum rough surfaces with 1D micro-structure at different incident angles are calculated with the rigorous coupled wave analysis (RCWA) method. The optical constants are then derived from the SE parameters to simulate the experimental optical constants determination process by SE. By comparing the optical constants derived from the SE parameters with the true values, the effects of micro-roughness and incident angle are analyzed. The results show that the relative errors of the optical constants increase with the surface micro-roughness, and the RL model could reduce the influence of the roughness effectively. Moreover, the relative errors decrease significantly with increasing incident angle. It concludes that the accuracy of the optical constants determined by SE could be improved by reducing the surface roughness and performing the SE measurements at large incident angles.