Studies Of Light Scattering On Anisotropic Si Wafer

The random surfaces are important parts in nature. It is very important to study it， and itis essential for many aspects，such as the dynamics of film’s growth、rupture aroused byconcussion of orb、the design of micro-electronics component and so on. So many peoplehave paid attention to studying about random surfaces for a long time. The fractal frameworkof random surfaces is generally non-smooth in short range, and the frame liked grain isshowed in long scale. The model of self-affine random surfaces can describe both theself-similitude in height of surfaces and the frame liked grain. In this paper, we are using themodel of self-affine random surfaces to study surface characteristics of anisotropic siliconwafers and monocrystalline silicon solar cells.Based on the scattering theory, we usually study the various characteristics of anisotropicrandom surface of the light scattering from the wave vector space, so it is necessary totransform the light scattering profiles of the actual space into wave vector space. The relevantliteratures are transformed in the one-dimensional direction. In this paper, the transformationrelation between actual space and wave vector space is deduced in theory. We transform thetwo-dimensionalactual spatial distribution of the light scattering profiles into the wave vectorspace concretely and study the distribution of light scattering profiles of two-dimensionalanisotropic random surface, providing important reference for further studies on the lightscattering properties of anisotropic random surfaces. The whole paper is divided into fivechapters.In chapter1, we give the Significance of this paper and introduce the description ofrandom surfaces and its measurements briefly.In chapter two, according to the Kirchhoff approximation theory, the function of lightscattering profile is deduced in wave vector space, and the light scattering characteristics ofself-affine fractal random surfaces、mounded surfaces and non-Gaussian surfaces is analyzed.In chapter three, the morphology of silicon wafer and monocrystalline silicon solar cellsare studied with atomic force microscope. We find the height-height correlation functionH ()and the auto-correlation function Rh ()，and the Root-mean-square roughness w、the lateral correlation length and the roughness exponent of a random surface sample can be extracted.In chapter four, we use anisotropic silicon samples. Using the receiver screen to receivethe scattering pattern, the lens to image the scattering pattern on the receiver screen, thescattering pattern is collected with the CCD. The light scattering intensity profiles arecalculated at different incident angles （40o~80o）on silicon wafer. According to therelationship of light scattering profile between actual spatial space and wave vector space, wetransform the actual spatial distribution of the light scattering profiles into the wave vectorspace concretely and study the distribution of light scattering profiles of two-dimensionalanisotropic random surface.In chapter5, we give the summary of this paper and put forward the further goal.