摘要
椭偏仪是薄膜测量的重要工具。从模拟和实验两方面,描述一种新颖的单波长椭偏仪的校准方法。该方法的基本思路是:如果被测样品的相关信息(折射率n,吸收系数k,厚度d)已知,则可以通过测量光强变化的傅里叶系数,采用最小二乘法原理反演出此时椭偏系统的信息(即校准参数,包括起偏器方位角P,检偏器方位角A,波片起始旋转角Cs,波片位相延迟δ,系统入射角θ0)。利用校准得到的系统参数和测量未知样品得到的光强傅里叶系数,求得未知样品的厚度。该方法具有操作简单、节约成本等优点。分别针对2～6个样品尝试了校准,对该校准方法做了模拟分析。将该方法用于实际测量,考证校准后的测量效果,并做了误差分析,最大误差为0.26nm。
Ellipsometry is an important measurement tool for thin films. A novel calibration method is described for single wavelength ellipsometry, both theoretically （with simulation） and experimentally. The basic idea is as follows： if the relevant information （refractive index n, absorption coefficient k, thickness d） of samples is given prior to measurements, the system calibrating parameters （angle of polarizer P, angle of analyzer A, offset angle of compensator Cs, phase shift of compensator δ, and angel of incidence θ0） can be deduced from the comparison of the measured and calculated Fourier coefficients, with the least square method. These calibrated system parameters can then be used to measure unknown samples. This method is easy to implement and cost-saving. 2 - 6 samples have been tested in the calibrations, and the errors are analyzed with simulation. Finally, this method is applied to a realistic 632.8 nm laser ellipsometer, and the results obtained with the new calibration method prove the validity of the method and show a maximum error of 0.26 nm.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2013年第4期84-91,共8页
Acta Optica Sinica
基金
国家重大专项(2011ZX02101-005)资助课题
关键词
薄膜
椭偏校准方法
最小二乘法
校准参数
模拟和实验分析
thin films
ellipsometry calibration method
least square method
calibration parameter
analysis in simulation and experiment
