We use a finite element software (Comsol Multiphysics) to study the kinetics of DNA hybridization and the potential limitation of the reaction rate caused by diffusion effects. The value of the parameters influencing the kinetics can sometimes span several orders of magnitude. Therefore, a wide range of values was used in order to cover the conditions seen in DNA microarrays. The competition between specific and non specific hybridization is also studied. In the cases where hybridization is diffusion limited, a convective transport is added to successfully overcome this limitation.