Growth kinetics of nanoscale SiO2 layer in a nitric oxide (NO) ambient

Nanoscale (less than or equal to 5 nm) SiO2 films have been grown in a nitric oxide (NO) ambient as a function of oxidation temperature and time. The overall growth follows the linear-parabolic model proposed by Deal and Grove. The chemical etching profiles of the NO-oxide films indicate a much lower etching rate near the SiO2/Si interface as compared to that of pure SiO2 film. This behavior is evidenced by the fact that the reaction of NO molecules with the silicon surface produces a nitrogen-rich interfacial layer (similar to 7.3 at%) which acts as a barrier to an oxidant passing through the SiO2/Si interface. The temperature dependence of the rate constant B indicates that the activation energy changes at 1000 degrees C: below 1000 degrees C, activation energy is 1.4 eV and above 1000 degrees C, it is 4.0 eV. The reason for this change is thought to be the decomposition of NO gas that occurs at temperatures above 1000 degrees C.