ELECTRICAL-ACTIVITY AND PRECIPITATION BEHAVIOR OF COPPER IN GALLIUM-ARSENIDE

The electrical properties and preferred lattice site of Cu in GaAs wer e investigated combining electrical and optical measurements with ion beam and structural analysis. From this comprehensive study it was det ermined that Cu introduces two levels in the band gap, that the concen tration of electrically active centers introduced by Cu diffusion is c onsiderably smaller than the total Cu concentration, that this ratio o f electrically active to total Cu concentration depends strongly on th e cooling speed after diffusion, and that the portion of Cu that remai ns electrically inactive forms Cu-Ga precipitates.