The influence of classic and rapid thermal annealing pretreatments under nitrogen or hydrogenated ambients on thermal donor formation and on the further oxygen nucleation step were studied. A rapid thermal annealing at 1200 degrees C under a nitrogen ambient delayed the formation of thermal donors. If nitrogen was replaced by a hydrogenated ambient, thermal donor formation was largely enhanced. In each case further nucleation was affected. A modification of the precipitation path due to rapid thermal annealing is proposed to be at the origin of the tremendous effect of a prior lamp anneal on the internal gettering process. The classic heterogeneous nucleation of the platelets would be prevented and the precipitation would proceed through a homogeneous path leading to precipitates unable to getter metal impurities.