Origin of self-limiting oxidation of Si nanowires.

A new kinetic model is suggested to describe the self-limiting oxidation of Si nanowires by only considering the diffusion step with the influence of stress due to the two-dimension nonuniform deformation of the oxide but not including any rate-limiting step for interfacial reaction. It is assumed the stress results in the change of distribution of diffusion activation energy in the high density region which rises monotonically along with the oxidation, and may be the main physical origin of the self-limiting oxidation behavior of SiNWs. Moreover, the present kinetic model can excellently describe the experimental results for the wide initial diameter over the range of self-limiting oxidation temperature.