Accession Number : ADA320710

Title :   Ion Scattering and Deposition: The Role of Energetic Particles in Thin Film Growth.

Descriptive Note : Final rept. 1 Sep 93-31 Aug 96,

Corporate Author : CORNELL UNIV ITHACA NY LAB OF ATOMIC AND SOLID STATE PHYSICS

Personal Author(s) : Cooper, Barbara H.

PDF Url : ADA320710

Report Date : 14 JAN 1997

Pagination or Media Count : 9

Abstract : We have used Ultra High Vacuum Scanning Tunneling Microscopy (UHV-STM) to investigate the evolution of morphology on metal surfaces irradiated with energetic ion beams. Time-lapse images were used to observe the stability and decay of isolated islands and pits subsequent to the irradiation. We developed theoretical analytic models and Monte Carlo simulations to describe island decay. Key results are: (1) monolayer height islands and pits are formed in the early stages of energetic Ar irradiation of Au(111); (2) under certain experimental conditions islands decay over time; (3) analytic models of island decay based on the Gibbs-Thomson effect predict different decay rates and laws depending on the relative magnitudes of parameters that describe different macroscopic decay processes; (4) comparisons of the analytic model to simulations of island decay give insights into how these macroscopic decay parameters are determined by microscopic surface processes. These studies are part of a larger effort to probe mechanisms of thin film deposition with energetic ion beams; additional projects include (i) the development of a new beamline and ultra high vacuum system for in-situ STM studies of thin films deposited with hyperthermal energy ions, and (ii) scattering studies of the mechanisms of hyperthermal energy ion trapping at surfaces.

Descriptors :   *METALS, *SCATTERING, *MORPHOLOGY, *THIN FILMS, *ION BEAMS, *DEPOSITION, *PARTICLES, *ENERGETIC PROPERTIES, MATHEMATICAL MODELS, SIMULATION, TIME INTERVALS, PROBES, LAYERS, GROWTH(GENERAL), HIGH TEMPERATURE, ENERGY, ISOLATION, TRAPPING(CHARGED PARTICLES), MONTE CARLO METHOD, MICROSCOPY, SURFACES, IMAGES, VACUUM APPARATUS, IRRADIATION, DECAY, ISLANDS, ULTRAHIGH VACUUM.

Subject Categories : Inorganic Chemistry
      Particle Accelerators
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE