Ab initio calculations of As-vacancy interactions in silicon

摘要

Atomistic simulation of a vacancy-assisted dopant diffusion in silicon needs details of the dopant-vacancy interaction, i.e., the potential as a functional of dopant-vacancy separations. In this paper, the authors present a detailed study on the energetics of As-vacancy reaction in silicon and the lattice distortions surrounding the As-vacancy defect by using an ab initio plane wave pseudopotential method and the density functional theory (DFT). A potential-energy diagram as a function of As-vacancy separation is provided, which can be used in the atomistic diffusion simulations. The authors also calculate the binding energy and the formation energy of different complexes such as AsV, As(sub 2)V and AsV(sub 2) (V represents vacancy). They find that the stable configuration of As(sub 2)V is As-V-As, while the stable configuration of AsV(sub 2) is As-V-V. The nature of the binding between As and vacancy is explained from the lattice distortions and the change of chemical bond configuration introduced by the As-vacancy complex.