Vacancy-mediated dopant diffusion in silicon was investigated using Monte Carlo simulations of hopping diffusion, as well as analytic approximations based upon atomistic considerations. Dopant/vacancy interaction potentials were assumed to extend out to third-nearest neighbor distances, as required for pair diffusion theories. An analysis which focused on the third-nearest neighbor sites as bridging configurations for uncorrelated hops led to an improved analytical model for vacancy-mediated dopant diffusion. The Monte Carlo simulations of vacancy motion on a doped silicon lattice confirmed analytical results for moderate doping levels. At very high doping (≳ 2 x 1020/cm3) the simulations indicated a very rapid increase in pair diffusivity due to interactions of vacancies with more than one dopant atom. This behavior had previously been observed experimentally for group IV and V atoms in silicon (Nylandsted Larsen et al., 1993), and the simulations predicted both the point of onset and doping dependence of the experimentally observed diffusivity enhancement. Atomistic Models of Vacancy-Mediated Diffusion in Silicon. S.T.Dunham, C.D.Wu: Journal of Applied Physics, 1995, 78[4], 2362-6