S‐implanted GaAs at room temperature was annealed by several seconds radiation from halogen lamps. Differential Hall effect/sheet resistivity measurements have been used to study the annealing behavior and electrical carrier concentration profiles of S‐implanted GaAs. Electrical activation was found to increase with increasing annealing temperature up to 1100 °C. A maximum electrical activation of 78% was obtained for a dose of 5×1013cm−2. Also, more than 5×1018cm−3peak carrier concentration was obtained for a dose of 1×1014cm−2, indicating about three times higher peak concentration than that obtained after conventional furnace annealing. For higher doses, the implanted S in the annealed GaAs does not follow Gaussian distribution even after rapid annealing. Damage‐enhanced outdiffusion of S is considered to be responsible for this result.