Migration of Si adatom on strained Si(1 1 1) surfaces

Quantum chemical calculations were performed to indicate the lowest energy path and the activation energy for Si adatom diffusion on a Si(1 1 1) surface and to evaluate the dependency of the activation energy on strains imposed on the Si surface. The activation energy barrier for the adatom diffusion was estimated to be 0.8 eV for a non-strained surface. The energy barrier increases on Si surfaces under compressive strain and, conversely, decreases under tensile strain. However, the energy variations are only within 0.1 eV under strains ranging between ±1%. The influence of strain on the 7×7 reconstruction is discussed in light of these theoretical results.