Ellipsometric Parameters of Rough Surfaces and of a System Substrate-Thin Film with Rough Boundaries

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Abstract
The theory of the influence of surface roughness on the ellipsometric parameters j and of simple randomly rough surface is developed in the framework of the Kirchhoff theory of diffraction. This theory is also extended to the following systems: rough surface—isotropic homogeneous identical film (both ambient-film and film substrate boundaries are geometrically identical; and rough surface—isotropic homogeneous general film (both boundaries are geometrically, and therefore also statistically, independent). Also the numerical analysis of the theoretical results is performed and the most important aspects of dependencies of j and on surface roughness (characterized by slopes of the height irregularities) and of the angle of incidence are found which enable us to determine the values of these slopes. The correctness of the theory is demonstrated on a system formed by the rough surface of a silicon single crystal covered with natural surface film, with the character of an identical film. It is shown that we can distinguish fairly well between the influence of surface roughness and that of a thin surface film on j and at certain conditions.