We characterize the transition structure at the $\mathrm{S}\mathrm{i}(100)\mathrm{\text{−}}{\mathrm{S}\mathrm{i}\mathrm{O}}_2$ interface by addressing the inverse ion-scattering problem. We achieve sensitivity to Si displacements at the interface by carrying out ion-scattering measurements in the channeling geometry for varying ion energies. To interpret our experimental results, we generate realistic atomic-scale models using a first-principles approach and carry out ion-scattering simulations based on classical interatomic potentials. Silicon displacements larger than $0.09\AA$ are found to propagate for three layers into the Si substrate, ruling out a transition structure with regularly ordered O bridges, as recently proposed.

• Received 5 September 2002

DOI:https://doi.org/10.1103/PhysRevLett.90.186101