 The study investigates the diffusion of tin, SN, atoms from a SN-doped bulk substrate to an epitaxial layer during heat treatment at temperatures ranging from 1050 to 1250 degrees Celsius. The results suggest that SN diffusion occurs via the formation and dissociation of intermittent mobile VGASNGA complexes, which are mediated by GA vacancy, VGA, migration. The evolution of the SN concentration versus depth profile was successfully modeled using a reaction diffusion equation with a VGASNGA complex migration barrier of 3.0 EV and a diffusion coefficient of 2 times 10 to the power of negative 1 cm2 slash s. These values are consistent with those predicted by the nudged elastic band method, which showed migration barriers of 3.42, 3.15, and 3.37 EV for the 100, 010, and 001 directions, respectively. This article is authored by Amor K. Frotten, Patrick P. Krasaniak, Lassay Vines, and others. We are article.tv, links in the description below.