Sem-Ebic Characterization of Semiconducting and Semi-Insulating LEC-GaAs

We have applied the SEM-EBIC technique (electron-beam-induced current method using a scanning electron microscope) to the characterization of both semiconducting and semi-insulating liquid encapsulated Czocralski (LEC) grown GaAs and have found this technique to be effective for semiinsulating materials as well as semiconducting ones. In semiconducting Si-, In- and undoped LEC-GaAs, growth striations were observed under usual measurement conditions. In semi-insulating undoped LEC-GaAs, clear EBIC images of individual dislocations and cell structures of dislocations were obtained by applying a high reverse bias voltage of about 10∼100 V to the specimens. We have also investigated nearly dislocation-free semiinsulating In-doped LEC-GaAs and found inhomogeneities which are different from those observed in undoped specimens. The spatial resolution of this technique is estimated to be 2–3 μm, which agrees with the experimental result