Oxygen diffusion through the disordered oxide network during silicon oxidation

An atomic-scale description is provided for the long-range oxygen migration through the disordered SiO2 oxide during silicon oxidation. First-principles calculations, classical molecular dynamics, and Monte Carlo simulations are used in sequence to span the relevant length and time scales. The O2 molecule is firmly identified as the transported oxygen species and is found to percolate through interstices without exchanging oxygen atoms with the network. The interstitial network for O2 diffusion is statistically described in terms of its potential energy landscape and connectivity. The associated activation energy is found in agreement with experimental values.