基于不同色散模型的TiO_(2)薄膜的椭偏光谱分析

Ellipsometric analysis of TiO_(2)thin films based on different dispersion models

为了研究不同色散模型对含孔隙TiO_(2)薄膜的椭偏光谱分析的影响,分别采用5种色散模型对溶胶-凝胶法制备的TiO_(2)薄膜在1.55—4 eV波长范围内的椭偏光谱进行拟合分析,并利用斜反射谱对各模型的拟合结果进行验证。结果表明:不同色散模型的选择对薄膜厚度和孔隙率的拟合结果均有影响,折射率色散的拟合结果受色散模型影响明显,New-Amorphous、Tauc-Lorentz、Adachi-New Forouhi模型均适用于溶胶-凝胶法TiO_(2)薄膜在整个测试波段上的椭偏光谱拟合,而Cauchy Absorbent、Sellmeier Absorbent模型无法在整个测试波段得到较好的椭偏光谱拟合,适用波段较窄。该研究结果为含孔隙的溶胶-凝胶TiO_(2)薄膜的椭偏光谱分析提供了色散模型选择参考。

In order to study the effects of different dispersion models on the ellipsometry spectra analysis of TiO_(2)films containing pores,TiO_(2)thin films are prepared by sol-gel method,and five dispersion models are used to fit the ellipsometry spectra of TiO_(2)films in the wavelength range of 1.554 eV.The fitting results of each model are verified by the oblique reflection spectra.The results show that the selection of different dispersion models has an effect on the fitting results of film thickness and porosity,and the fitting results of refractive index dispersion are obviously affected by the dispersion model.New-Amorphous,Tauc-Lorentz and Adachi-New Forouhi models are suitable for the ellipsometry spectra fitting of sol-gel TiO_(2)film on the whole test band.However,the Cauchy Absorbent and Sellmeier Absorbent models cannot get a good ellipsometric spectral fitting for the whole test band,and the applicable band is narrow.The results provide a reference for the ellipsometry spectra analysis of sol-gel TiO_(2)thin films containing pores.