AVS 52nd International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuM

Paper PS-TuM7
Molecular Dynamics Simulations of Ar@super +@ Bombardment of Si: Characterizing Ion-Induced Disorder at Surfaces

Tuesday, November 1, 2005, 10:20 am, Room 304

Session: Plasma Surface Interactions I
Presenter: D. Humbird, Lam Research Corporation
Authors: D. Humbird, Lam Research Corporation
D.B. Graves, University of California at Berkeley
W.M.M. Kessels, Eindhoven University of Technology, The Netherlands
Correspondent: Click to Email
Previous molecular dynamics (MD) simulations of energetic Ar@super +@ ions bombarding initially crystalline Si surfaces indicated the formation of an amorphous phase of Si on top of crystalline Si. This amorphous phase is established within 1 monolayer of Ar@super +@ fluence, and under continuous bombardment it reaches a steady-state thickness that is a function of the impacting ion energy. We revisit some of these calculations with a different potential energy function that predicts the same general behavior, but also permits accurate simulation of F atoms interacting with a Si surface. We discuss changes to the average Si-Si bond length, bond angle, and other local order parameters as a result of Ar@super +@-induced amorphization. We note sharp transitions of these properties at the interface between amorphous and crystalline Si. Finally, we discuss differences in uptake and etch rate when thermal F atoms adsorb on and spontaneously etch the amorphous and crystalline surfaces. Some parallels are drawn between the simulations and recent real-time ellipsometry and second harmonic generation experiments, which give information on amorphous layer formation, and on bond disorder at the interface and surface of the amorphous layer, respectively.