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 estimate d by means of X-ray photoelectron spectroscopy XPS . With use of the p eak decomposition technique and angle-resolved XPS (ARXPS), the distri bution of the silicon nitride and oxide in the films is determined. Bo th the nitride and oxide thicknesses are evaluated. The thickness dete rmined by XPS agrees with the thickness determined by cross-sectional transmission electron microscopy (TEM). This XPS method is valid for e stimation of the thickness and composition of ultrathin silicon nitrid e films, and it has the advantages of accuracy over ellipsometry and c onvenience over TEM.