Analysis of peculiar structural defects created in GaAs by diffusion of copper

High spatial resolution and high-sensitivity techniques, such as DSL etchin g, AFM and TEM, have been used to analyse peculiar structural defects creat ed in GaAs by Cu diffusion. They consist of(lj entangled grown-in dislocati ons surrounded by dislocation loops, (2) clusters of dislocation loops and (3) (0 0 1) complex planar defects revealed as square-like etch features on the (0 0 1) etch surface or as (I 0 0) linear etch features when these pla nar defects lie in the (1 0 0) or (0 1 0) planes perpendicular to the sampl e surface. The (1 0 0) linear defects are due to straight dislocation segme nts decorated by precipitates whereas the (0 0 1) defects are ascribed to l oops from the clusters of type (2) that have selectively grown to a size mu ch larger than the other ones. All these defects are surrounded by regions of enhanced etch rate. Their formation is ascribed to the interaction betwe en point defects created during Cu diffusion that presumably occurs by the kick-out mechanism, whereby Cu-Ga and Ga interstitials are formed. (C) 2000 Published by Elsevier Science B.V. All rights reserved.