The measured activation energies for oxide growth rates at the initial and late stages of oxidation of Si are 2 and 1.2 eV, respectively. These values imply that oxidation can proceed at temperatures much smaller than the 800 °C normally used to obtain devices with exceptionally smooth $\mathrm{Si}\mathrm{\text{−}}{\mathrm{SiO}}_2$ interfaces. Here, we use first-principles calculations to identify the atomic-scale mechanisms of the 2 eV process and of additional processes with higher barriers that control the interface morphology and ultimately provide for smooth layer-by-layer oxide growth, as observed at high temperatures.

• Received 19 May 2006

DOI:https://doi.org/10.1103/PhysRevLett.97.116101