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S. Messaadi

Bio: S. Messaadi is an academic researcher. The author has contributed to research in topics: Thin film & Scattering. The author has an hindex of 3, co-authored 7 publications receiving 27 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a simple analytical expression for the electrical conductivity of polycrystalline, monocrystalline and columnar metal films can be obtained in the whole experimental domain and may conveniently replace the sophisticated expression of Mayadas and Shatzkes.
Abstract: Previous studies have shown that the Cottey function constitutes an alternative formulation for the Fuchs-Sondheimer size-effect function, provided that a new parameter is used. This result is used for calculating the effects of scattering at a grain boundary, and a good agreement with the Mayadas-Shatzkes model is found. When background, grain-boundary and external-surface scattering are simultaneously operative, a simple analytical expression for the electrical conductivity of polycrystalline, monocrystalline and columnar metal films can be obtained in the whole experimental domain and may conveniently replace the sophisticated expression of Mayadas and Shatzkes. This expression is similar to that obtained in the framework of the multidimensional models, previously presented. No limitation exists in the value of the electronic specular reflection coefficient, and the theoretical expression is related both to annealed and unannealed films.

16 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the size effect in thin metal films can be easily described with the aid of a mean free path (m.f.p) related to this scattering effect, even when multidimensional phenomena are taken into account.
Abstract: Theoretical studies [1] have shown that the size effect in thin films can be conveniently described with the aid of a mean free path (m.f.p.), the Cottey m.f.p., related to this scattering effect; this procedure had been suggested earlier by Cottey [2] and further theoretical studies have extended the range of validity to the calculation of any transport property [3], even when multidimensional phenomena are taken into account. A recent analysis [4] has established that a m.f.p. exhibiting the general form of the Cottey m.f.p, gives an interpretation for the calculation of the size effects in the pioneering work of Sondheimer [5], provided that an adequate algebraic representation of the alterations in the electron flow (due to the scattering at an external surface) be used. Moreover, the scattering phenomena due to phonons and external surfaces may be regarded as independent [4], without altering the agreement between the data derived from the FuchsSondheimer model [5] and from the extended Cottey model [4] within an inaccuracy of less than 6%, whatever the electronic specular reflection coefficient at the film surface may be. Consequently, the multidimensional models of conduction, which implement mean free paths related to any source of scattering, can be used for calculating any transport property of annealed and unannealed metal films, as recently discussed [6].

3 citations

Journal ArticleDOI
TL;DR: In this paper, an effective relaxation time is used for representing the effects of electronic scattering in thin metallic films from sources other than grain boundaries; the total conductivity of the film is then expressed in terms of the product of an alternative Fuchs-Sondheimer function with an effective grain-boundary multidimensional function.
Abstract: An effective-relaxation-time is used for representing the effects of electronic scattering in thin metallic films from sources other than grain boundaries; the total conductivity of the film is then expressed in terms of the product of an alternative Fuchs-Sondheimer function with an effective grain-boundary multidimensional function. The reduced Hall coefficient is then obtained in the form of the product of the reduced Fuchs-Sondheimer Hall coefficient with an effective reduced grain-boundary Hall coefficient. Qualitative agreement with experimental data is obtained.

2 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the resistance of Pt and Nifilms has been measured during deposition (by ion-beam sputtering) for different deposition rates r and substrate temperaturesT S (300≤T S ≤575 K).
Abstract: The resistanceR f of Pt and Nifilms has been measured during deposition (by ion‐beam sputtering) for different deposition rates r and substrate temperaturesT S (300≤T S ≤575 K). At the onset of deposition (the nucleation stage) R f varies only slowly with deposition time T and oscillations occur in R f vs T which are damped at the larger values of r,T S . Over the second stage, during which the metallic nuclei grow in size, R f decreases over many orders of magnitude and the R f versus fractional coverage x behavior is described by percolation‐type equations around a critical thickness t c . The film thickness t min (=rT min) at which the film becomes continuous (x=1) is identified with the minimum in the Rt 2 vs t graph. For t≳t min the R f vs t behavior is described by surface and grain‐boundary scattering equations, the derived values of grain size are related to T S , r, and compared with transmission electron microscope observations. Postdeposition temperature cycling measurements on filmsdeposited at T S =300 K show predominantly thermally activated conduction for t

77 citations

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TL;DR: In this paper, the authors present a theoretical model of lattice thermal conductivity in a silicon nanowire with square cross section taking into account the modifications of the acoustic phonon dispersion and boundary scattering on the side walls.
Abstract: We present a theoretical model of lattice thermal conductivity in a silicon nanowire with square cross section. This model takes into account the modifications of the acoustic phonon dispersion and boundary scattering on the side walls. A good approximation of exact lattice thermal conductivity is obtained by the yielded precise phonon dispersion relations under the xyz algorithm of Nishiguchi et al. [J. Phys.: Condens. Matter 9, 5751 (1997)] and the inclusion of three scattering events on the side walls from the phonon Boltzmann transport equation. Comparison is also made with the thermal conductivity of a cylindrical nanowire.

30 citations

Journal ArticleDOI
TL;DR: In this article, the size-dependent thermal conductivities of the nanowires are obtained by taking into account interface scattering, grain boundary scattering, and interface roughness effect, and the fractal model is also used to predict the contribution of interface Roughness to the thermal conductivity of nanowire.
Abstract: Thermal conductivity of copper and tungsten nanowires, copper damascene structures are modeled theoretically on the basis of Boltzmann transport equation. The size-dependent thermal conductivities of the nanowires are obtained by taking into account interface scattering, grain boundary scattering, and interface roughness effect. Expressions for the thermal conductivity of thin films including the above mechanisms are extended to the case of rectangular cross-sectional nanowires. The fractal model is also used to predict the contribution of interface roughness to the thermal conductivity of nanowires. It is shown that the interface roughness is important for the nanowires with lateral dimensions down to the sub-30 nm region. Calculated thermal conductivities are in good agreement with the experimental data for copper and tungsten nanowires. Furthermore, it is found that the titanium nitride barrier layer obviously leads to further thermal conductivity reduction in the copper damascene structures.

23 citations

Journal ArticleDOI
TL;DR: In this article, the temperature coefficient of resistivity (t.c.r.) has been studied for polycrystalline metal tin and lead films of various thicknesses, and it has been shown that the thickness dependence of t.cr.r. is successfully explained with the help of a threedimensional model.
Abstract: The temperature coefficient of resistivity (t.c.r.) has been studied for the polycrystalline metal tin and lead films of various thicknesses. The t.c.r. is found to increase with thickness and thus exhibits the size effect. This thickness dependence of t.c.r. is successfully explained with the help of a three-dimensional model. The grain boundary t.c.r. and specularity parameter are determined from the measurements.

10 citations

Journal ArticleDOI
TL;DR: In this paper, the authors interpret the result on grain boundary resistivity of tin and lead films with the help of the Mayadas and Shatzkes model and that of Pichard et al.
Abstract: The size dependence of electrical resistivity of polyvalent metal films have been of interest for many years. Katyal et al. have studied the electrical properties of thin metallic tin and lead films. They found that average grain size increases with the film thickness and resistivity is consistent with the Mayadas model for completely diffuse scattering, i.e. p=0. The aim of this paper is to interpret the result on grain boundary resistivity of tin and lead films with the help of the Mayadas and Shatzkes model and that of Pichard et al.

7 citations