We report on the results of a study of the influence of rapid thermal annealing (RTA) on the diffusivity and solubility limit of titanium and chromium in silicon. It is shown that RTA has no influence on the diffusion of the metal atoms as long as the treatment is performed with the metal silicide as the boundary phase, but that the diffusivity is decreased if silicidation occurs during RTA. On the other hand, a strong solubility enhancement is found to occur during RTA.