12,217 research outputs found
Analysis of thin-film structures with nuclear backscattering and x-ray diffraction
Backscattering of MeV ^(4)He ions and Seemann-Bohlin x-ray diffraction techniques have been used to study silicide formation on Si and SiO_2 covered with evaporated metal films. Backscattering techniques provide information on the composition of thin-film structures as a function of depth. The glancing-angle x-ray technique provides identification of phases and structural information. Examples are given of V on Si and on SiO_2 to illustrate the major features of these analysis techniques. We also give a general review of recent studies of silicide formation
Influence of bandwidth restriction on the signal-to-noise performance of a modulated PCM/NRZ signal, part 2
Analyzing effects of bandlimiting on performance of digital transmission corrupted by additive white Gaussian noise by averaging and series expansio
Surface morphological evolutions on single crystal films by strong anisotropic drift-diffusion under the capillary and electromigration forces
The morphological evolution of voids at the unpassivated surfaces and the
sidewalls of the single crystal metallic films are investigated via computer
simulations by using the novel mathematical model developed by Ogurtani relying
on the fundamental postulates of irreversible thermodynamics. The effects of
the drift-diffusion anisotropy on the development of the surface morphological
scenarios are fully explored under the action of the electromigration (EM) and
capillary forces (CF), utilizing numerous combination of the surface textures
and the directions of the applied electric field. The interconnect failure time
due to the EM induced wedge shape internal voids and the incubation time of the
oscillatory surface waves, under the severe instability regimes, are deduced by
the novel renormalization procedures applied on the outputs of the computer
simulation experiments.Comment: 41 pages, 18 figures. related simulation movies utilizing numerous
combination of the surface texture, see
http://www.csl.mete.metu.edu.tr/aytac/thesis/movies/index.ht
Identification of the dominant diffusing species in silicide formation
Implanted noble gas atoms of Xe have been used as diffusion markers in the growth study of three silicides: Ni2Si, VSi2, and TiSi2. Backscattering of MeV He has been used to determine the displacement of the markers. We found that while Si atoms predominate the diffusion in VSi2 and TiSi2, Ni atoms are the faster moving species in Ni2Si
Comprehensive HIV care and Anti-Retroviral Therapy in a conflict setting-outcomes, experiences, and lessons learned from Bukavu, Democratic Republic of Congo
2006 AIDS Conference in Toront
The role of Joule heating in the formation of nanogaps by electromigration
We investigate the formation of nanogaps in gold wires due to
electromigration. We show that the breaking process will not start until a
local temperature of typically 400 K is reached by Joule heating. This value is
rather independent of the temperature of the sample environment (4.2-295 K).
Furthermore, we demonstrate that the breaking dynamics can be controlled by
minimizing the total series resistance of the system. In this way, the local
temperature rise just before break down is limited and melting effects are
prevented. Hence, electrodes with gaps < 2 nm are easily made, without the need
of active feedback. For optimized samples, we observe quantized conductance
steps prior the gap formation.Comment: including 7 figure
Event-specific chorus wave and electron seed population models in DREAM3D using the Van Allen Probes
Abstract The DREAM3D diffusion model is applied to Van Allen Probes observations of the fast dropout and strong enhancement of MeV electrons during the October 2012 double-dip storm. We show that in order to explain the very different behavior in the two dips, diffusion in all three dimensions (energy, pitch angle, and Lo) coupled with data-driven, event-specific inputs, and boundary conditions is required. Specifically, we find that outward radial diffusion to the solar wind-driven magnetopause, an event-specific chorus wave model, and a dynamic lower-energy seed population are critical for modeling the dynamics. In contrast, models that include only a subset of processes, use statistical wave amplitudes, or rely on inward radial diffusion of a seed population, perform poorly. The results illustrate the utility of the high resolution, comprehensive set of Van Allen Probes\u27 measurements in studying the balance between source and loss in the radiation belt, a principal goal of the mission. Key Points DREAM3D uses event-specific driving conditions measured by Van Allen Probes Electron dropout is due to outward radial diffusion to compressed magnetopause Event-specific chorus and seed electrons are necessary for the enhancement
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