AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Wednesday Sessions
       Session NS-WeA

Paper NS-WeA8
Formation of Large-Area Nanostructures on Si and Ge Surfaces during Low-Energy Ion Beam Erosion

Wednesday, November 2, 2005, 4:20 pm, Room 210

Session: Nanopatterning and Manipulation
Presenter: B. Ziberi, Leibniz-Institut für Oberflächenmodifizierung e.V. Leipzig, Germany
Authors: B. Ziberi, Leibniz-Institut für Oberflächenmodifizierung e.V. Leipzig, Germany
F. Frost, Leibniz-Institut für Oberflächenmodifizierung e.V. Leipzig, Germany
B. Rauschenbach, Leibniz-Institut für Oberflächenmodifizierung e.V. Leipzig, Germany
Correspondent: Click to Email
In contrast to advanced lithographic methods and subsequent etching procedures for pattern production with structure size < 100 nm, which are complex technological processes, self-organized spontaneous pattern formation during low-energy ion beam erosion is a cost-efficient `bottom up` approach for the fabrication of large-area nanostructures. The formation of these patterns can be observed on various semiconductor materials and is attributed to a surface instability between curvature dependent sputtering that roughens the surface and smoothing by different surface relaxation mechanisms. In these work results for pattern formation due to low-energy noble gas (Ne@super +@, Ar@super +@, Kr@super +@, Xe@super +@) ion beam erosion of silicon and germanium surfaces at oblique ion incidence with and without sample rotation are presented. Depending on ion beam parameters, i. e. ion energy, ion incidence angle and ion mass, different patterns can evolve on the surface. In the case with sample rotation, very well ordered dot structures evolve on the Si surface at glancing incidence angle of 75° with respect to surface normal, with size varying from 30 nm to 50 nm. Without sample rotation, at small ion incidence angles, remarkably high ordered ripple patterns with wavelength ~ 50 nm can form on both materials for similar sputtering conditions. By further increasing the ion incidence angle a transition from ripples to highly hexagonally ordered dot structures with periodicity of ~ 40 nm are observed. The lateral ordering of nanostructures increases with erosion time, leading to very well ordered and homogenous structures. The mean size of nanostructures can be adjusted with ion energy while maintaining their lateral ordering. Scanning force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM) were used to study the lateral ordering, shape, and size of these nanostructures.