The transport of dopants within the lattice is not only controlled by the diffusion mechanism, there are also recombination processes between dopants and point-defects occurring, which can disturb or even prevent dopants from diffusion. These recombinations are always possible when dopant-defect pairs are approaching lattice defects of the opposite type. If the dopant concentration level is significantly below the intrinsic carrier concentration, the diffusivities of the dopants show no dependence on the doping level.

In the subsequent section we will focus on two practical circumstances in which the diffusion can be carried out. Diffusion from an unlimited source (Constant source diffusion) occurs when a wafer is exposed to an infinite amount of dopants during the diffusion period. In the case of diffusion from a limited source, a finite quantity of the dopants is first placed on the wafer and diffusion proceeds from this limited source and it is assumed that all the dopants are consumed.