The enhanced disordering of GaAs/AlGaAs superlattices by diffusion of Zn or Si has been reported by many authors. In the case of Si diffusion, the Si can be introduced during epitaxial growth, by implantation, or by diffusion from a sputtered Si mask. In this paper ion implantation is investigated, and the effect of rapid thermal annealing (RTA), used to minimize Si diffusion while eliminating the implant damage, is compared with furnace annealing (FA). Using low temperature photoluminescence (PL) and SIMS, it is found that no disordering of a GaAs/Al0.5Ga0.5As superlattice takes place for a 2 sec anneal at 900°C, and very minimal partial disordering is observed (reproducibly) for a 10 sec anneal at 970°C. This is in sharp contrast with the FA case (850°C for 30 min), for which significant disordering occurs. The PL spectra show luminescence from both GaAs and GaAs/Al0.5Ga0.5As layers in the case of high-temperature RTA suggesting that recrystallization has occurred without disorder, whereas strong emission is observed after FA which corresponds to a disordered layer of average-composition GaAs/Al0.15Ga0.25As In both cases, PL indicates that annealing of the implant damage has occurred. Thus, damage can be eliminated either with or without disordering the superlattice by using FA or RTA, respectively. This is important for 2-D electron gas structures, for which no broadening of the hetero-interface is desired.