INTERFACIAL DAMAGE IN ION-IRRADIATED GAAS ALAS SUPERLATTICES/

Damage creation at GaAs/AlAs/GaAs interfaces during irradiation with M eV Kr and Ar ions was investigated by ion channeling experiments. The GaAs layers became amorphous while the AlAs layers showed unusual dama ge behavior. At one interface, AlAs on GaAs, an amorphous phase grows into the AlAs while at the opposite interface, GaAs on AlAs, the AlAs remains crystalline. The asymmetry is also observed in samples with fi ve alternating layers; amorphization occurs at the two AlAs on GaAs in terfaces but not the GaAs on AlAs interfaces. The rate at which the am orphous layer grows does not depend on the deposited damage energy alo ne, but rather depends on the ratio of the ionization to damage energi es, demonstrating the importance of ionization in the damage process. At large ratios of ionization to damage energies, the growth rate can be zero or even negative.