We have grown ∼10 nm O2and N2O‐oxides on Si(100) by RTO (rapid thermal oxidation) over the temperature range 800–1200 °C. Although the growth rates of both oxides exhibit Arrhenius behavior over the entire temperature range, the N2O‐oxides exhibit a large change in the Arrhenius preexponential factor for oxidation temperatures greater than 1000 °C. Above this temperature, N2O‐oxides grow a factor of 5 slower than O2oxides. Below this temperature, N2O‐oxide growth rates approach those of O2‐oxides. This growth rate inflection can be explained in terms of N incorporation, which increases with increasing oxidation temperature. The equivalent of one monolayer of N coverage is achieved at about 1000 °C, coincident with the inflection. The incorporated N retards the linear growth of the thin N2O‐oxides either by occupying oxidation reaction sites or inhibiting transport of oxidant species to the vicinity of the interface. ©1995 American Institute of Physics.