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Low-energy As+-ion implantation followed by rapid thermal annealing (RTA) was utilized to modify exciton transition energies of GaAs/AlGaAs quantum wells (QW). A variety of structures were irradiated at an energy low enough that the disordered region was spatially separated from the QWs. After RTA, exciton energies showed large increases which were dependent on QW widths and the implantation fluence with no significant increases in peak linewidths. The observed energy shifts were interpreted as resulting from the modification of the shapes of the as-grown QWs due to enhanced Ga and Al interdiffusion at heterointerfaces in irradiated areas. These results are consistent with the model of enhanced intermixing of Al and Ga atoms in depth of the material due to diffusion of vacancies generated near the surface.

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A new approach for capless rapid thermal annealing of ion implanted III-V semiconductors, the enhanced overpressure proximity (EOP) technique, has been developed and applied to GaAs implanted with Si+. The EOP method relies on the use of a Sn-coated GaAs wafer to provide a localized arsenic overpressure around the ion implanted wafer during the annealing cycle. The arsenic overpressure resulting from this arrangement is greater than the overpressure obtained with the conventional proximity method, which utilizes an untreated GaAs wafer as an arsenic source. This new annealing technique has yielded higher electrical activation and electron mobilities in GaAs than the conventional proximity method as well as an increased latitude in annealing times and temperatures. The EOP approach can be easily extended for capless rapid thermal annealing of other III-V compounds such as InP and InGaAs.

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