ESTIMATION OF THE THICKNESS OF ULTRATHIN SILICON-NITRIDE FILMS BY X-RAY PHOTOELECTRON-SPECTROSCOPY

The thickness and composition of ultrathin silicon nitride films which are deposited on Si substrates and on thin thermal oxide are estimated by means of X-ray photoelectron spectroscopy XPS . With use of the peak decomposition technique and angle-resolved XPS (ARXPS), the distribution of the silicon nitride and oxide in the films is determined. Both the nitride and oxide thicknesses are evaluated. The thickness determined by XPS agrees with the thickness determined by cross-sectional transmission electron microscopy (TEM). This XPS method is valid for estimation of the thickness and composition of ultrathin silicon nitride films, and it has the advantages of accuracy over ellipsometry and convenience over TEM.