Diffusion and Clustering in Heavily Arsenic-Doped Silicon: Discrepancies and Explanation

Very different concentration dependences of As diffusivity in heavily doped silicon have been observed, but a consistent explanation of the underlying atomic-scale process is lacking. We present an extensive first-principles study on the As-vacancy interactions in heavily doped silicon in terms of which we have explained quantitatively the driving mechanism of the observed enhanced diffusion and revealed the time dependence of the redistribution of dopant atoms. By checking the details of As-vacancy interaction potential and the time dependence of diffusion and clustering, we find that the discrepancies between different experiments and between different atomistic simulations eventually disappear.