Nitrogen transport during rapid thermal growth of silicon oxynitride films in N2O

We investigated the transport of nitrogenous species during rapid thermal growth of silicon oxynitride films on Si in N2O, using N isotopic tracing and high resolution depth profiling techniques. The results indicate that the diffusion of nitrogenous species (most probably NO) through the growing oxynitride film to react with Si at the oxynitride/Si interface, induces the incorporation of N near this interface. This mechanism acts in parallel with a site-to-site jump mechanism (interstitialcy or vacancy) of diffusion and chemical reaction of nitrogenous species in the volume of the growing oxynitride film. The characteristic N accumulation only near the interface obtained by rapid thermal processing growth in N2O is due to the removal of N from the near surface region of the films, here attributed to atomic exchanges O<->N taking place during growth. Furthermore, N<->N exchange was also observed. (C) 1996 American Institute of Physics.