Striations in Undoped Semi-Insulating LEC GaAs

Abstract
Striations in undoped semi-insulating GaAs grown by liquid encapsulated Czochralski (LEC) technique were revealed by photoetching with diluted AB etchant and X-ray transmission topography. The striations had two different periods; one with shorter period of about 30 µm was due to crystal rotation, and the other with longer period of about 300 µm was due to melt convection. The formation of the striations in undoped semi-insulating GaAs was ascribed to stoichiometric inhomogeneity.