Characterization of the impurity profile at the SiO2/Si interface using a combination of total reflection X-ray fluorescence spectrometry and successive etching of silicon

During the fabrication process of integrated circuits, dopant atoms segregate to energetically favorable sites at the interface between silicon and silicon dioxide. Because of the continuously shrinking device dimensions, this effect becomes even more significant. To describe it quantitatively within the framework of Technology Computer-Aided Design, the concentration profile at and near the SiO2/Si interface has to be characterized accurately. Total Reflection X-ray Fluorescence Spectrometry (TXRF) with successive etching was used to determine the impurity profile at the SiO2/Si interface with a resolution on the order of a nanometer.