Damage production in GaAs and GaAsN induced by light and heavy ions

Ion irradiation causes damage in semiconductor crystal structures and affects charge carrier dynamics. We have studied the damage production by high-energy (100 keV-10 MeV) H, He, Ne, and Ni ions in GaAs and GaAs90N10 using molecular dynamics computer simulations. We find that the heavier Ne and Ni ions produce a larger fraction of damage in large clusters than H and He. These large clusters are either in the form of amorphous zones or (after room-temperature aging or high-temperature annealing) in the form of vacancy and antisite clusters. The total damage production in GaAs and GaAs90N10 is found to be practically the same for all the ions. A clearly smaller fraction of the damage in GaAs90N10 compared to GaAs is in large clusters, however. Our results indicate that experimentally observed differences in charge carrier lifetimes between light and heavy ion irradiations, and before and after annealing, can be understood in terms of the large defect clusters. An increasing amount of damage in large clusters decreases the carrier decay time. (c) 2006 American Institute of Physics.