Nanoscale Morphology Control Using Ion Beams

Abstract

Ion irradiation of a solid surface can be used to control surface morphology on length scales from 1 micron to 1 nanometer. Focused or unfocused ion irradiation induces a spontaneous self-organization of the surface into nanometer-sized ripples, dots, or holes; it also induces diameter increases and decreases in pre-existing nanopores. The phenomenology of the surface morphological evolution under ion beam erosion is reviewed with an emphasis on semiconducting materials, including recent experiments on the influence of boundary conditions on guiding self-organized pattern formation; the development of shock fronts that sharpen features at sufficiently steep angles; and the kinetics governing the fabrication of nanopores for single-biomolecule detectors. The theory underlying the surface morphology evolution is reviewed and areas of agreement and disagreement with experiment are identified.