INTERACTION OF COPPER WITH DISLOCATIONS IN GAAS

The interaction of copper with dislocations was studied in silicon-dop ed gallium arsenide by means of cathodoluminescence, analytical, and t ransmission electron microscopy. Several structures of defect complexe s or microdefects surrounding the dislocations were found depending on the diffusion temperature and cooling rate. The results could be expl ained by considering the local nonequilibrium of intrinsic point defec ts induced by Cu in- or outdiffusion. The appearance of a bright or da rk dislocation contrast in the cathodoluminescence pictures is related for different diffusion conditions: i) to the enrichment of copper ac cepters at dislocations, ii) to the distribution of silicon-vacancy co mplexes, and iii) to non-radiative recombination at Cu-As precipitates or clouds of small dislocation loops.