AVS 53rd International Symposium
    Advanced Surface Engineering Wednesday Sessions
       Session SE-WeM

Paper SE-WeM4
Super Poisson Growth through Glancing Incidence Deposition

Wednesday, November 15, 2006, 9:00 am, Room 2007

Session: Glancing Angle Deposition
Presenter: H. Wormeester, MESA+ Institute for Nanotechnology, Netherlands
Authors: H. Wormeester, MESA+ Institute for Nanotechnology, Netherlands
F.L.W. Rabbering, MESA+ Institute for Nanotechnology, Netherlands
T. Warnaar, MESA+ Institute for Nanotechnology, Netherlands
B Poelsema, MESA+ Institute for Nanotechnology, Netherlands
Correspondent: Click to Email
Short - and long range attractive forces between a substrate and an incoming atom result in a morphology dependent heterogeneous flux. Already at submonolayer coverage, this flux heterogeneity leads to shape anisotropy of Cu-ad-structures on Cu(001). With increasing coverage the anisotropy becomes progressively larger and above 20 ML strongly rectangular mounds have formed. The anisotropy has been revealed by high resolution electron diffraction. For Co on Cu(001) also the formation of a strongly uniaxial magnetic axis was observed. The evolution of the morphology as a result of the steering effect, the change in trajectory of incoming atoms as a result of attractive forces has been modeled within a kMC scheme that takes into account many of the diffusion processes known to occur on the Cu(001) surface. Simulations show that pure geometric shadowing does not lead to the reproduction of most of the experimentally observed anisotropy features. However, the incorporation of the steering effect does allow to reproduce many of the experimental details. The focus of the flux near ascending steps results in a strong increase of the roughness of the grown layer. For normal incidence, the roughness increases finally with an exponent @beta@=0.5, i.e. a Poisson distributed roughness, while initially even growth oscillations are observed. Above a polar angle of incidence of 60°, the roughness increase is much larger and exponents up to @beta@=2 are found, i.e. super Poisson roughness. Both the asymmetry and the strong roughness increase bear potential for technological applications.