Core-level intensities for Si 2p, Si2s, O1s, and N1s were measured by x-ray photoelectron spectroscopy in bulk samples of silicon, SiO2 and Si3N4. A complete and consistent set of intensity ratios is given and applied for calculations of thickness and stoichiometry in thin Si/oxide/nitride layers, which can be used for gate dielectrics in advanced metal–oxide–semiconductor field-effect transistor fabrication.