A comparison of infrared spectroscopic analytical approaches was made in order to assess their applicability for internal structure characterization of SiO₂ thin films. Markers for porosity and/or disorder based on the analysis of the asymmetric stretching absorption band of SiO₂ between 900−1350 cm⁻¹ were discussed. The shape of this band, which shows a well-defined LO–TO splitting, depends not only on the inherent characteristics of the film under analysis but also on the particular geometry of the IR experiment and the specific surface selection rules of the substrate. Three types of SiO₂ thin films with clearly defined porosity ranging from dense films to mesoporous films were investigated by transmission (at different incidence angles), direct specular reflection (at different angles), and diffuse reflection. Two different types of substrate, metallic and semiconducting, were used. The combined effect of substrate and specific technique in the final shape of the band, was discussed, and the efficacy for their applicability to the determination of porosity in thin SiO₂ films was critically evaluated.

进行了红外光谱分析方法的比较，以评估其在SiO ₂薄膜内部结构表征中的适用性。基于对SiO ₂在900-1350 cm ^-1之间的不对称拉伸吸收带的分析，讨论了孔隙率和/或无序性的标志。该条带的形状显示出明确的LO–TO分裂，不仅取决于被分析膜的固有特性，还取决于IR实验的特定几何形状以及基材的特定表面选择规则。三种类型的SiO ₂通过透射（在不同的入射角），直接镜面反射（在不同的角度）和漫反射研究了具有清晰定义的孔隙率的薄膜，从致密膜到中孔膜。使用了两种不同类型的基底，金属基底和半导体基底。讨论了基底和特定技术在带的最终形状中的综合作用，并严格评估了其在确定SiO ₂薄膜中孔隙率方面的适用性。