Model of thermal oxidation of silicon at the volume-reaction front

A model of thermal oxidation of silicon, which interacts with an oxidizer at the volume-reaction front, is developed. The width of the reaction zone corresponds to the width of the transition layer with the violated stoichiometry (δ ≈ 7.5 Å). The oxidizer-diffusivity relaxation is taken into account from its value in stressed silicon dioxide to that in unstressed silicon dioxide, which is equal to the fused-quartz diffusivity. The relaxation is related to the structural reconstruction in amorphous silicon dioxide as it moves away from the reaction-zone boundary. The model describes well the thermal-oxidation kinetics of silicon in dry oxygen within a wide range of silicon dioxide thicknesses including the initial stage.