O2 oxidation reaction at the Si(100)-SiO2 interface: A first-principles investigation

We investigated the oxidation reaction of the O2 molecule at the Si(100)-SiO2 interface by using a constrained ab initio molecular dynamics approach. To represent the Si(100)-SiO2 interface, we adopted several model interfaces whose structural properties are consistent with atomic-scale information obtained from a variety of experimental probes. We addressed the oxidation reaction by sampling different reaction pathways of the O2 molecule at the interface. The reaction proceeds sequentially through the incorporation of the O2 molecule in a Si-Si bond and the dissociation of the resulting network O2-species. The oxidation reaction occurs nearly spontaneously and is exothermic, regardless of the spin state of the O2 molecule. Our study suggests a picture of the silicon oxidation process entirely based on diffusive processe