A study of the dislocations in Si-doped GaAs comparing diluted Sirtl lightetching, electron-beam-induced current, and micro-Raman techniques

Impurity atmospheres around dislocations have been studied in n-type Si-dop ed liquid encapsulated Czochralski (LEC) GaAs substrates by micro-Iiaman sp ectroscopy, diluted Sirtl-like etching with light (DSL) method, and electro n-beam-induced current (EBIC). A complete morphological study of the recomb inative atmospheres revealed by photoetching was achieved by phase stepping microscopy (PSM), which is an optical interferometry technique allowing to obtain the surface topography with a high vertical resolution (tin the nan ometer range). The minority carrier diffusion length was measured by EBIC a t different points of the atmospheres. Structural distortion at the regions surrounding the dislocation core were observed by micro-Iiaman spectroscop y. The carrier depletion depth and the recombination of the photogenerated carriers were also studied by Raman spectroscopy, obtaining a good agreemen t with the EBIC data and the photoetching rates. Impurity gettering and dif fusion and defect reactions involving As interstitials are assumed to play a major role in the formation of the recombinative atmospheres.