椭偏方法分析无氢DLC薄膜光学吸收特性

类金刚石（Diamond Like Coobon，DLc）薄膜在光学领域主要用做红外区高强度减反射光学薄膜，准确测定薄膜的消光系数走，是评价薄膜吸收特性的关键环节．考虑到DLc薄膜材料结构的复杂性，研究了椭偏技术在分析无氢DLC薄膜时物理模型的建立方法，并且验证了该模型分析结果的准确性．利用Maxwell—Gamett等效介质理论建立了一种单层椭偏分析物理模型Si／EMA（n，＋n2混合材料），利用该模型探索了采用双层模型的高低折射率比值代替薄膜中不同结构材料组分比值的有效性，从整体上用单层模型表征了DLc薄膜的消光系数，获得了单层薄膜的消光系数和折射率．测试了样片的透射率光谱．分别采用TFC（TFCalc）拟合的透射率光谱和Raman光谱验证了椭偏分析模型测试结果的准确性为椭偏分析技术研究DLC薄膜吸收损耗特性提供了有效路径．

Study on the Optical Absorption of Free-hydrogen Diamond-like Carbon Films by Ellipsometric Method

Diamond-like carbon thin film is used as high hardness and anti-reflection film, accurate determination of the extinction coefficient of the film is a key part of the evaluation of thin-film absorption properties. Taking into account the non-unity of the material structural properties of DLC films, a new single physical model is established by using equivalent medium theory. The effectiveness of using double layer model of high and low refractive index ratio instead of different components ratio is explored based on this new model. The extinction coefficient of DLC thin film is characterized overall by single layer model. The accuracy of the ellipsometric model test results is verified by transmittance and Raman spectroscopy. The results explicitly show the methods and conditions about initial value selection of the model, and provide a effective path of ellipsometric analysis technique to study the optical absorption of free-hydrogen diamond-like carbon films.