单晶硅球法是阿伏伽德罗常数量值精密测量以及质量重新定义的一种重要方案。单晶硅球表面的氧化层厚度关系到硅球质量和直径测量结果的修正,并在阿伏伽德罗常数的相对测量不确定度中占到很大比例。讨论了表面层测量中影响椭偏测量的几个基本问题,即单晶硅球不同晶向的光学常数以及表面曲率对椭偏光束的散射效应,评估了对氧化层厚度测量不确定度的影响;对于所采用的间接法的不确定度分量进行了分析。该研究为硅球表面层测量提供了实验和理论依据。 Monocrystalline silicon ball method is a measure of Avogadro constant precision measurement and quality redefinition of an important program. The thickness of the oxide layer on the surface of the monocrystalline silicon sphere is related to the correction of the mass and diameter measurements of the silicon sphere and accounts for a large proportion of the relative measurement uncertainty of Avogadro’s constant. Several basic problems that affect ellipsometry in surface layer measurement are discussed, that is, the optical constants of different directions of single crystal silicon sphere and the scattering effect of surface curvature on the elliptically polarized beam, and the influence on the measurement uncertainty of oxide layer thickness The uncertainty component of the indirect method used was analyzed. The research provided the experimental and theoretical basis for the measurement of the surface of silica spheres.