The effects of heating rate on the recrystallization and dopant activation, for samples under different implant conditions, have been studied. The as-implanted samples were annealed, at various heating rates, to different preset temperatures but zero holding time. Factors associated with the dopant activation have been evaluated to develop a proper activation mechanism, thus correlating with the experimental results. In the transient annealing, a higher heating rate facilitates the dopant activation via a lower effective activation energy, while lower heating rates inherently own longer effective activating times. Implant conditions strongly determine the degree, impacting the dopant activation, of respective factors. In addition, higher heating rates led to better Si recrystallization.