利用透射光谱与X射线反射谱精确测量溶胶-凝胶TiO_2薄膜厚度和光学常数

Determination of Thickness and Optical Constants of Sol-Gel Derived TiO_2 Films by Combined Analysis of Transmittance and X-Ray Reflectivity Spectra

在洁净K9玻璃基底上沉积TiO2薄膜,将透射光谱和X射线反射光谱相结合分析获得膜层的厚度和光学常数。X射线反射谱拟合能精确得到膜层的厚度、电子密度及表面和界面粗糙度,其中膜层厚度的数值为透射光谱的分析提供了重要参考。基于Forouhi-Bloomer色散模型拟合膜层透射光谱,得到薄膜折射率和消光系数,理论曲线和实验曲线吻合良好。对于同一样品,两种光谱拟合分析得到的厚度数值非常接近,差值最大为4.9nm,说明两种方法的结合能够提高光学分析结果的可靠性。

TiO2 films deposited on well clean K9 glass substrates are investigated for their thickness and optical constants by transmittance and X-ray reflectivity （XRR） measurements. XRR provides highly accurate results on film electron density, thickness and interface roughness. The film thickness from XRR is used as an anitial value to accelerate the evaluation of the transmittance data. With the help of Forouhi-Bloomer dispersion model, the calculated transmittance curves fit the experimental results well. For the same sample, the film thickness values from the two methods are very close and the maximum difference is 4.9 nm, which indicates that the combination of XRR and transmittance spectra can improve the reliability of the optical characterization.