Mixed polarization in determining the film thickness of a silicon sphere by spectroscopic ellipsometry  

作　　者：Zhang Ji-Tao Wu Xue-Jian Li Yan 张继涛;吴学健;李岩(State Key Laboratory of Precision Measurement Technology&Instruments,Department of Precision Instruments and Mechanology,Tsinghua University,Beijing 100084,China)

机构地区：[1]State Key Laboratory of Precision Measurement Technology&Instruments,Department of Precision Instruments and Mechanology,Tsinghua University,Beijing 100084,China

出　　处：《Chinese Physics B》2012年第1期147-152,共6页中国物理B（英文版）

基　　金：Project supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(Grant No.2006BAF06B06);the Tsinghua University Initiative Scientific Research Program,China(Grant No.2009THZ06057)

摘　　要：The effect of a spherical shape on the measurement result of spectroscopic ellipsometry （SE） is analyzed, and a method to eliminate this effect is proposed. Based on the simulation result of the SE measurement on a silicon sphere by ray tracking, we find that the sphere makes the parallel incident beam of the SE be divergent after reflection, and the measurement error of the SE caused by this phenomenon is explained by the mixed polarization theory. By settling an aperture in front of the detector of the SE, we can almost eliminate the error. For the silicon sphere with a diameter of 94 mm used in the Avogadro project, the thickness error of the oxide layer caused by the spherical shape can be reduced from 0.73 nm to 0.04 nm by using the proposed method. The principle of the method and the results of the experimental verification are presented.The effect of a spherical shape on the measurement result of spectroscopic ellipsometry （SE） is analyzed, and a method to eliminate this effect is proposed. Based on the simulation result of the SE measurement on a silicon sphere by ray tracking, we find that the sphere makes the parallel incident beam of the SE be divergent after reflection, and the measurement error of the SE caused by this phenomenon is explained by the mixed polarization theory. By settling an aperture in front of the detector of the SE, we can almost eliminate the error. For the silicon sphere with a diameter of 94 mm used in the Avogadro project, the thickness error of the oxide layer caused by the spherical shape can be reduced from 0.73 nm to 0.04 nm by using the proposed method. The principle of the method and the results of the experimental verification are presented.

关 键 词：spectroscopic ellipsometry silicon sphere Avogadro constant METROLOGY 

分 类 号：O484.5[理学—固体物理] TL81[理学—物理]