Thickness determination of very thin SiO2 films on Si by electron-induced x-ray emission spectroscopy

Electron-induced x-ray emission spectroscopy (EXES) associate with a semi-empirical electron scattering model is used to determine thicknesses between 2 and 21 nm of SiO2 films on Si. The small charging effect occurring upon electron irradiation is taken into account by introducing a retarding potential in the model. The results are in very close agreement with those obtained by spectroscopic ellipsometry and x-ray reflectometry. It is demonstrated that the EXES with its model is a well-suited method for the quantitative analysis of thin insulating films with an uncertainty lower than 5%.