ISOTOPIC TRACING DURING RAPID THERMAL GROWTH OF SILICON OXYNITRIDE FILMS ON SI IN O-2, NH3, AND N2O

We performed isotopic tracing of O, N, and H during rapid thermal grow th of silicon oxynitride films on silicon in two different sequential, synergistic gas environments: O-2, followed by NH3, then followed by N2O; and N2O, followed by NH3. Using nuclear reaction analysis and hig h resolution depth profiling, we demonstrate that the oxynitride films grow by means of thermally activated atomic transport involving the t hree traced species. Concomitantly, isotopic exchange processes take p lace. Growth in these sequential gas environments leads to oxynitride films with N concentration profiles and H concentrations different fro m those obtained by commonly used processes like thermal growth in N2O only or thermal nitridation of SiO2 films in NH3. (C) 1997 American I nstitute of Physics.