基于单晶硅原子计数原理实现阿伏加德罗常数精密测量以及质量千克单位的复现,需要测量单晶硅球体的质量和体积,球表面几个纳米厚的非均匀氧化层分布的精密测量,是确定上述参量修正值的关键。用劳厄晶向法和激光标记确定了硅球表面坐标系统,比较了不同的硅球驱动方式,建立了基于光谱椭偏仪的自动化扫描测量装置,考察了扫描系统的重复性、稳定性;给出了NIM#3号硅球扫描结果,表明表面氧化层椭偏扫描的短期重复性水平达到0.04 nm。 The precise measurement of Avogadro’s constant and the recurrence of mass kg units based on the single crystal silicon atomic counting principle require the measurement of the mass and volume of the single crystal silicon sphere, the precision measurement of the distribution of non-uniform oxide layers of several nanometers thick on the surface of the sphere , Is to determine the value of the above parameters correction key. The surface coordinate system of the silica sphere was determined by Laue crystal orientation and laser marking. Different driving ways of the silicon sphere were compared. An automated scanning and measuring device based on spectral ellipsometry was established. The repeatability and stability of the scanning system were investigated. The result of NIM # 3 silicon ball scanning is given, which shows that the short-term repeatability of surface oxide ellipsometry reaches 0.04 nm.