Observation of GaAs--AlxGa1--xAs heterostructures and quantum-well-wire structures using backscattered electron image.

As a microscale tool for observing GaAs-Alx Ga1-xAs heterostructures, backscattered electron (BE) images in the scanning electron microscope (SEM) were compared with conventional secondary electron (SE) images. BE images were found to be more sensitive to compositional differences between GaAs and AlxGa1-xAs and less sensitive to surface roughness. BE images have a spatial resolution of 10 nm or better. This method enables the nondestructive observation of ultrafine lateral periodic structures, such as quantum-well-wire (QWW) structures, fabricated by compositional disordering technology using focused Ga ion-beam (Ga-FIB) implantation into GaAs-AlxGa1-xAs material.