摘要
光谱椭偏仪是常用的测量薄膜厚度及材料光学性质的仪器，其准确性主要由系统的校准过程确定。提出一种新的利用标准样品校准光谱椭偏仪的方法。该方法通过对多个已知厚度和已知材料特性的薄膜样品进行测量，利用测量得到的多个样品的傅里叶系数光谱与包含未知校准参数的理论光谱之间进行对比，通过最小二乘法拟合，回归求解出整个系统的未知校准参数，包括偏振器方位角，波片延迟，波片方位角和系统入射角等。将该方法的应用领域扩展到2001000nm的宽光谱区域，并通过测量3～13nm的SiO2／Si薄膜样品，实验验证了该方法的有效性，准确性达到0．194nm。该方法相对于传统校准方法更加简单、快速。
Spectroscopic ellipsometer is a common instrument for measuring film thicknesses and optical properties, whose accuracy largely depends on the calibration procedure of ellipsometry system. We propose a new calibration method by measuring several standard thin film samples with known thickness and dielectric function to obtain the experimental Fourier coefficient spectra. Fit these spectra to theoretical spectra which includes the calibration parameters using least-squares method and then solve these parameters of the ellipsometry system, including the azimuth of polarized elements, the retardation of waveplate, the azimuth of waveplate and the incident angle etc, We have extended this method to broadband spectrum of 200- 1000 nm and verified the validity by measuring the SiO2 thin films in the thickness range of 3-13 nm and demonstrated good measurement accuracy of 0. 194 nm. This new method is easier and faster than traditional calibration method.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2014年第3期117-126,共10页
Acta Optica Sinica
基金
中国科学院科研装备研制项目(28Y3YZ018001)
国家重大专项资助项目(2011ZX02101-005)
关键词
薄膜
校准
光谱椭偏仪
最小二乘法
光学常数
thin films
calibration
spectroscopic ellipsometer
least-squares method
optical constants
