薄膜材料自仿射分形表面形貌的光散射标定方法的研究

Random self-affine fractal surface can reflect the growth fronts of thin films and is also of great importance in many fields of science and technology. The studies on the light scattering of random surfaces of this kind are sigincant in the point views of either basic scientific researches or the practical applications in the characterizations of random random surfaces in thin film growth and other areas. In the performance of this project, we first study the properties of the intensity profiles and the random light fields scattered from random self-affine fractal surfaces and find a variety of new properties in them, such as the flake structures in the light field and the power law decay behaviors in the scattered intensity profiles. By use of the substitution of the mathematical decay functions, we study the generic properties of the half-width of the intensity profiles, from which roughness and other surface parameters can be extracted without using the central peak in them. On the basis of the theoretical work, we make much advancement in the experimental method for the characterization and the measurement of the random self-affine fractal surfaces. Combining the measurement of the central peak of the scattered profiles with the optical inversion algorithms, we accomplish for the first time the extraction of the height probability density function of random surfaces by the scattering method. Using the variable aperture and the duple scattering method, we retrieve the height-height correlation function and conduct the simultaneous measurement of the three surface parameters of roughness , lateral correlation length and roughness exponent . We also deepen the studies of near-field light scattering of random fractal surfaces by the rigorous numerical solutions of the Green's integral of the light field, which would be of importance and significance for the exploration of new reseach areas.

本项目拟通过对中心光强导数法，单轮廓函数渐进法和数值逆运算法三种光散射测量方法的研究，实现对薄膜材料自仿射分形表面的粗糙度W，横向相关长度和粗糙指数A三个统计特征量的单轮廓光散射标定，并实现无镜面反射亮点时的粗糙度测量和对较粗糙表面的横向相关长度的测量。本项目对研究薄膜生长机理和制备高质量薄膜材料有重要应用前景。.