Excess Si and passivating N and F atoms near the pyrolytic-gas-passivated ultrathin silicon oxide film/Si(100) interface

Abstract

Number densities of Si, O, N, and F atoms near the 3.5–6.5-nm-thick silicon oxide film/Si(100) interface produced by a recently proposed in-situ passivation method [pyrolitic-gas passivation (PGP)] that uses a little pyrolytic N2O and NF3 gases were determined. It was found that the generation of excess Si atoms relative to the stoichiometric SiO2 composition near the interface is effectively inhibited by the localized passivating N and F atoms. Moreover, the number of excess Si decreases while those of N and F increase with decreasing humidity. These PGP effects can be confirmed only at a humidity of less than 1ppb. It is therefore believed that N and F passivations effectively contribute to compensate the residual inconsistent-state bonding sites near the interface that still remain through an extreme dehydration.