We have been making a series of papers for thin-film analysis techniques for characterization of crystalline qualities and crystal structures using High Resolution XRD (HR-XRD), or characterization of layer structures, such as film thickness, etc., using X-ray reflectivity (XRR) method. An X-ray analytical technique for the evaluation of particle/pore sizes will be explained in this paper.
Small Angle X-ray Scattering (SAXS) technique is a technique mostly used for characterization of the size distributions of particle sizes dispersed in liquid medium, or those of pores/textures in porous bulk samples. Due to the sample configuration, the analysis is used to be performed using transmission geometry through sample bodies. However, in applying this technique to thin film samples, a reflection geometry is required since the absorption due to thick substrates is the great obstacle to detect the weakly scattered signals from thin films or their surfaces. This situation is inevitable since nano- or sub-micron scaled surface textures or structures formed on sample surfaces are the main target of this analysis.
In this paper, a general feature of SAXS measurement and analysis with the transmission geometry will be briefly mentioned first. Then, details of SAXS measurement/analysis technique in transmission geometry applied for thin film samples will be shown together with the applications to the functional thin film samples.