X-ray investigation of low-energy ion-beam induced lateral surface nanostructures on semiconductor surfaces

Low energy ion beams are widely used to alter the surface properties of semiconductors. We have used two different ways to create lateral nanostructures, either using an artificial patterning by a focused ion beam or by a tilted non-focused ion beam achieving a self-organizing ripple formation. X-ray grazing-incidence diffraction is a powerful tool to investigate such lateral nano-structures. Choosing the angle of incidence smaller or slightly larger as the critical angle of total external reflection one can probe the fine structure of an in-plane Bragg diffraction in a depth between about 5 to several 100 nm.