Rapid thermal annealing (R TA) techniques are increasingly used in many technological applications. To date, however, only a limited knowledge exists of the efifects induced by these thermal treatments on the material characteristics. We have studied the defect equilibria in float zone (FZ) and Czochralski zone (CZ) silicon subjected to annealing at 400 C by employing two difl’erent heating techniques, namely electron beam and lamp system.