Anion inclusions in III-V semiconductors

On all surfaces cleaved from InP, GaP, GaAs, and GaSb a local excess of anion atoms was detected as bright spots in the image of the electron current absorbed by the samples and identified by using a scanning Auger electron spectrometer exhibiting a spatial resolution of 20 μm. Arsenic zones were detected on horizontal Bridgman- as well as liquid encapsulation Czochralski grown GaAs indicating their existence to be independent of the crystal growth technique. The densities of anion zones varied between 10 and 500 per square centimeter on a cleave-to-cleave basis. Their diameters typically measured approximately 50 μm. The investigations indicate that the anion zones originate from inclusions in the bulk becoming exposed by cleavage.