DISLOCATIONS AND PRECIPITATES IN SEMIINSULATING GALLIUM-ARSENIDE REVEALED BY ULTRASONIC ABRAHAMS-BUIOCCHI ETCHING

The dislocations and precipitates in SI-GaAs single crystals are revea led by ultrasonic-aided Abrahams-Buiocchi etching (USAB), and the etch pits are observed and measured by metalloscope and scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDS), respectively. The size of etch pit revealed by USAB etching is about 1 order of magnitude smaller than that revealed by molten KOH. The amount of arsenic atoms in the dislocation-dense zone is about 1% larger than that in an adjacent dislocation-free zone measured by EDS attached to SEM, which indicates that the excess arsenic atoms adjacen t to the dislocation-dense zone are attracted to the dislocations and precipitate there due to the deformation energy.