光学精密工程2012，Vol.20Issue(11)：2373-2379,7.DOI:10.3788/OPE.20122011.2373
非偏振分光镜对干涉式椭偏仪测量精度的影响
Influence of nonpolarizing beam splitters on measurement accuracy in interferometric ellipsometers
摘要
Abstract
A novel heterodyne interferometric ellipsometer was investigated to measure the thicknesses of thin films in the nanometer-accuracy. The depolarization effect of a Nonpolarizing Beam Splitter (NPBS) was characterized by the transmission-induced-retardance (TIR) between p and s components of a polarizing beam, reflectance ratio, transmittance ratio and reflection-induced-retardance (RIR), then a corresponding error model was established. The influence of the depolarization effect and mi-sorientation of a multi-layer dielectric NPBS on the errors of ellipsometric parameters was investigated. Experimental results indicate that the fluctuation of the depolarization effect caused by the environmental temperatures, incident angles and the change of polarizating state has a major impact on the measurement accuracy, and it can not be eliminated by calibration. In order to implement the nanometer-accuracy, the misorientation angle must be smaller than 0. 1? Furthermore, it shows that the NPBS orientation angle errors for recombination of the measurement light and the reference light have more important contribution than another ones to the measurement accuracy. The thickness measurement error of thin film induced by NPBS is about 1. 8 ?. 5 nm,which means that the NPBS is an assignable error source in the Mach-Zehnder interferometric ellipsometer.关键词
椭偏测量/干涉式椭偏仪/非偏振分光镜/膜厚测量/退偏效应/方位角误差Key words
ellipsometry/ interferometric ellipsometer/ film thickness measurement/ nonpolarizingbeam splitter/ depolarization effect/ misorientation angle分类
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邓元龙,李学金,耿优福,洪学明..非偏振分光镜对干涉式椭偏仪测量精度的影响[J].光学精密工程,2012,20(11):2373-2379,7.基金项目
国家自然科学基金资助项目(No.60978041) （No.60978041）
深圳市科技配套资助项目(No.ZYC201006090091A) （No.ZYC201006090091A）
