In the subject publication, Mathiot casts doubt upon our Monte Carlo s
imulations of Au diffusion in Si with the kick-out mechanism. We argue
that our simulations were correct. In addition, we observe that Mathi
ot's treatment of diffusion lacks information on boundary conditions w
hich is necessary for accurate modeling. Mathiot's model also ignores
the possible existence of vacancy clusters. Mathiot concluded that dif
fusion of Au in Si is dominated by the kick-out mechanism. We argue th
at this conclusion is unjustified.