The changes in diffusion rates of Sb, As, and P resulting from nitridation of SiO2 and direct nitridation of the silicon surface in NH3 ambient at 1100 °C are studied for times ranging from 7 min to 4.5 h. From analysis of these data we conclude that P must diffuse almost entirely by an interstitialcy mechanism at this temperature, and that previous formulations of dopant diffusion under nonequilibrium conditions may not be complete. We also determine that the effects seen during direct nitridation are better explained by a pure vacancy injection process than a pure self-interstitial depletion process, contrary to previous assertions by us and others.

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