Two-dimensional modeling of the self-limiting oxidation in silicon and tungsten nanowires

- A new diffusion-controlled kinetic model for nanowire oxidation is developed.
- A finite reactive region is included to account for oxidation stress and suboxide formation.
- Self-limiting nanowire oxidation and its curvature/temperature dependence are predicted.
- Results are consistent with observed oxidation behavior of silicon (Si) and tungsten (W) nanowires.

Self-limiting oxidation of nanowires has been previously described as a reaction- or diffusion-controlled process. In this letter, the concept of finite reactive region is introduced into a diffusion-controlled model, based upon which a two-dimensional cylindrical kinetics model is developed for the oxidation of silicon nanowires and is extended for tungsten. In the model, diffusivity is affected by the expansive oxidation reaction induced stress. The dependency of the oxidation upon curvature and temperature is modeled. Good agreement between the model predictions and available experimental data is obtained. The developed model serves to quantify the oxidation in two-dimensional nanostructures and is expected to facilitate their fabrication via thermal oxidation techniques.