DIFFUSION-INDUCED DEFECTS IN GAAS BY ZINC AND THE EFFECTS OF POST-DIFFUSION ANNEAL

The crystallographic defects generated during the diffusion of zinc into GaAs have been studied using transmission electron microscopy and chemical etching techniques. By observing the effects of arsenic pressure on the defect density and the zinc penetration, the annihilation of the diffusion-induced defects in relation to the surface stoichiometry was investigated. It was found that the dissolution of the defects within the crystal is mainly caused by the out-diffusion of the diffusion-induced Ga interstitials to the surface. This is also supported by results obtained from post-diffusion annealing of the samples under different arsenic pressures. In addition, the possible inclusion of arsenic atoms in the interstitial dislocation loops found in GaAs is also discussed.