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A. J. Tosser

Bio: A. J. Tosser is an academic researcher. The author has contributed to research in topics: Electrical resistivity and conductivity & Scattering. The author has an hindex of 11, co-authored 22 publications receiving 270 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the theoretical expression for the thermoelectric power of polycrystalline metal films is derived from an effective Fuchs-Sondheimer conduction model, and a procedure is proposed to determine the variation in the electronic mean free path.
Abstract: Starting from an effective Fuchs-Sondheimer conduction model, the theoretical expression for the thermoelectric power of polycrystalline metal films is derived. From the approximate expression for thick films, a procedure is proposed to determine the variation in the electronic mean free path.

64 citations

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TL;DR: In this article, a linear analytic expression for thin film conductivity and resistivity was proposed for a three-dimensional scattering model and from the mean free path representing the effect of electronic scattering on external surfaces.
Abstract: Starting from a three-dimensional scattering model and from the mean free path representing the effect of electronic scattering on external surfaces, a linear analytic expression is proposed for thin film conductivity and resistivity. Good agreement with experiment is found.

27 citations

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TL;DR: In this paper, the authors derived analytical expressions for the Hall coefficient and conductivity in thin polycrystalline metallic films subjected to a transverse magnetic field by using the Boltzmann transport equation.
Abstract: In polycrystalline films where three types of scattering processes (background, grainboundaries and external surfaces scatterings) are taking place at the same time an effective relaxation time is defined in the light of a three-dimensional model of grain-boundaries. Analytical expressions for the Hall coefficient and conductivity in thin polycrystalline metallic films subjected to a transverse magnetic field are then derived by using the Boltzmann transport equation. Previously published data can be theoretically interpreted in terms of the proposed model.

20 citations

Journal ArticleDOI
TL;DR: Theoretical formulations of strain coefficient of resistance and resistivity in supported and unsupported thin metallic films are examined in this paper, where the case of thermal strains is emphasised and an expression of the difference in TCR of supported and supported films is derived.
Abstract: Theoretical formulations of strain coefficient of resistance and resistivity in supported and unsupported thin metallic films are examined. The case of thermal strains is emphasised and an expression of the difference in TCR of supported and unsupported films is derived.

17 citations

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


Cited by
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Journal ArticleDOI
01 Mar 2001
TL;DR: This result emphasizes that changes in design, technology, and architecture are needed to cope with the onslaught of wiring demands and one potential solution is 3-D integration of transistors, which is expected to significantly improve interconnect performance.
Abstract: Twenty-first century opportunities for GSI will be governed in part by a hierarchy of physical limits on interconnects whose levels are codified as fundamental, material, device, circuit, and system. Fundamental limits are derived from the basic axioms of electromagnetic, communication, and thermodynamic theories, which immutably restrict interconnect performance, energy dissipation, and noise reduction. At the material level, the conductor resistivity increases substantially in sub-50-nm technology due to scattering mechanisms that are controlled by quantum mechanical phenomena and structural/morphological effects. At the device and circuit level, interconnect scaling significantly increases interconnect crosstalk and latency. Reverse scaling of global interconnects causes inductance to influence on-chip interconnect transients such that even with ideal return paths, mutual inductance increases crosstalk by up to 60% over that predicted by conventional RC models. At the system level, the number of metal levels explodes for highly connected 2-D logic megacells that double in size every two years such that by 2014 the number is significantly larger than ITRS projections. This result emphasizes that changes in design, technology, and architecture are needed to cope with the onslaught of wiring demands. One potential solution is 3-D integration of transistors, which is expected to significantly improve interconnect performance. Increasing the number of active layers, including the use of separate layers for repeaters, and optimizing the wiring network, yields an improvement in interconnect performance of up to 145% at the 50-nm node.

572 citations

Journal ArticleDOI
TL;DR: The efficiency of a thermoelectric material is determined by the dimensionless figure of merit as discussed by the authors, which is a function of the temperature difference between the hot and cold ends of the material.
Abstract: Thermoelectric materials convert a temperature difference into electricity and vice versa. [1–3] Such materials utilize the Seebeck effect for power generation and the Peltier effect for cooling. In the Seebeck effect, a temperature difference across a material causes the diffusion of charged carriers across that gradient, thus creating a voltage difference between the hot and cold ends of the material. Conversely, the Peltier effect explains the fact that when current flows through a material a temperature gradient arises because the charged carriers exchange thermal energy. Thermoelectrics perform these functions without moving parts or toxic gases, which make them unique among power generation and cooling methods. Presently, thermoelectrics find only limited use because of their poor efficiency. The efficiency of a thermoelectric material is determined by the dimensionless figure of merit

189 citations

Journal ArticleDOI
TL;DR: A new method for the measurement of thermal conductivity of electrically conducting single nanowires is presented and decreases of lambda, sigma and beta can be attributed to size effects, mainly caused by grain boundary scattering of electrons.
Abstract: A new method for the measurement of thermal conductivity of electrically conducting single nanowires is presented. First experimental investigations are focused on the thermal conductivity of metallic Pt nanowires with a diameter of (typically) 100 nm and a length of 10 µm. Thermal conductivity data are compared with measurements of electrical conductivity in order to test the Wiedemann–Franz law for metallic nanowires. Compared to the bulk values at room temperature, electrical and thermal conductivities of the nanowire are decreased by a factor of 2.5 and 3.4, respectively. Consequently, the Lorenz number L = λ/σT = 1.82 × 10−8 V2 K−2 of the nanowire is smaller than the bulk Lorenz number Lbulk = (π2/3)(k/e)2 = 2.44 × 10−8 V2 K−2 of metals. Furthermore, the temperature coefficient β of electrical resistivity is also reduced compared to the bulk value. These decreases of λ, σ and β can be attributed to size effects, mainly caused by grain boundary scattering of electrons.

133 citations

Journal ArticleDOI
TL;DR: In this article, the authors highlight the problems associated with interpreting data on the resistivity of thin thin films and point out that extreme care must be taken in analysing data and a thorough study should be made of the morphology of the films from which data are taken.
Abstract: This article highlights the problems associated with interpreting data on the resistivity of thin films. It is pointed out that extreme care must be taken in analysing data and a thorough study should be made of the morphology of the films from which data are taken. Without this, values deduced for parameters such as the surface roughness, the specularity and in particular the product of the bulk resistivity and the bulk mean free path are worthless. Even when the scattering contributions from the surface and the grain boundaries are taken properly into account, because of the high defect and dislocation densities in many of the films studied the values deduced for these parameters are still in doubt.

119 citations

Journal ArticleDOI
TL;DR: In this paper, the thickness dependence of the conductivity of copper, aluminium, silver, gold, nickel and platinum films was measured with high accuracy for various conditions of the evaporation.
Abstract: The thickness dependence of the conductivity of copper, aluminium, silver, gold, nickel and platinum films was measured with high accuracy for various conditions of the evaporation. The Fuchs-Namba model was the only one which could be fitted to the experimental data. Four parameters were determined: σ∞, l ∞, p and h . The ratioσ∞/l∞ is not a constant of the material but depends on the crystallite size. The related effective electron density n ∞ is less than the value n b for bulk single-crystal material. The method employed allows us to separate to volume and surface effects on the conductivity as well as to separate the scattering of electrons inside the crystallites from the reflections of electrons by the crystallite boundaries.

92 citations