The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Falk Schubert - One of the best experts on this subject based on the ideXlab platform.
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Three dimensional image-based simulation of ultrasonic wave propagation in Polycrystalline Metal using phase-field modeling
Ultrasonics, 2016Co-Authors: Kousuke Nakahata, Hideki Sugahara, M. Barth, B Kohler, Falk SchubertAbstract:When modeling ultrasonic wave propagation in Metals, it is important to introduce mesoscopic crystalline structures because the anisotropy of the crystal structure and the heterogeneity of grains disturb ultrasonic waves. In this paper, a three-dimensional (3D) Polycrystalline structure generated by multiphase-field modeling was introduced to ultrasonic simulation for nondestructive testing. 3D finite-element simulations of ultrasonic waves were validated and compared with visualization results obtained from laser Doppler vibrometer measurements. The simulation results and measurements showed good agreement with respect to the velocity and front shape of the pressure wave, as well as multiple scattering due to grains. This paper discussed the applicability of a transversely isotropic approach to ultrasonic wave propagation in a Polycrystalline Metal with columnar structures.
Kousuke Nakahata - One of the best experts on this subject based on the ideXlab platform.
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Three dimensional image-based simulation of ultrasonic wave propagation in Polycrystalline Metal using phase-field modeling
Ultrasonics, 2016Co-Authors: Kousuke Nakahata, Hideki Sugahara, M. Barth, B Kohler, Falk SchubertAbstract:When modeling ultrasonic wave propagation in Metals, it is important to introduce mesoscopic crystalline structures because the anisotropy of the crystal structure and the heterogeneity of grains disturb ultrasonic waves. In this paper, a three-dimensional (3D) Polycrystalline structure generated by multiphase-field modeling was introduced to ultrasonic simulation for nondestructive testing. 3D finite-element simulations of ultrasonic waves were validated and compared with visualization results obtained from laser Doppler vibrometer measurements. The simulation results and measurements showed good agreement with respect to the velocity and front shape of the pressure wave, as well as multiple scattering due to grains. This paper discussed the applicability of a transversely isotropic approach to ultrasonic wave propagation in a Polycrystalline Metal with columnar structures.
Yoshio Nishi - One of the best experts on this subject based on the ideXlab platform.
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Theory and Experiments of the Impact of Work-Function Variability on Threshold Voltage Variability in MOS Devices
IEEE Transactions on Electron Devices, 2012Co-Authors: Xiao Zhang, Jerome Mitard, Lars-ake Ragnarsson, Tomas Hoffmann, Michael Deal, Melody E. Grubbs, Jing Li, Blanka Magyari-kope, Bruce M. Clemens, Yoshio NishiAbstract:A model for work-function variability (WFV) based on grain orientation differences of the Polycrystalline Metal gate is proposed, and the impact of the WFV on device and circuit performance is investigated. The model predicts that the WFV will surpass random dopant fluctuation beyond the 22-nm technology node and become the dominant factor to significantly increase static RAM failure probabilities. The prediction is verified through experimental characterization and analysis.
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physical model of the impact of Metal grain work function variability on emerging dual Metal gate mosfets and its implication for sram reliability
International Electron Devices Meeting, 2009Co-Authors: Xiao Zhang, Michael Deal, Melody E. Grubbs, Jing Li, Bruce M. Clemens, Blanka Magyarikope, Yoshio NishiAbstract:A new model of work function variability (WFV) based on grain orientation differences of the Polycrystalline Metal gate is reported. Our model predicts that at the 22nm technology node, among the three device variability sources: random dopant fluctuation (RDF), line edge roughness (LER) and WFV, WFV will cross over RDF and becomes the dominating factor. The SRAM circuit analysis shows that write/read failures are underestimated by 9 orders of magnitude by the area weighted averaged work function model.
S Suresh - One of the best experts on this subject based on the ideXlab platform.
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size effects on the mechanical properties of thin Polycrystalline Metal films on substrates
Acta Materialia, 2002Co-Authors: Yoonjoon Choi, S SureshAbstract:An analysis of the effects of the thickness and grain size of Polycrystalline thin films on substrates is presented with the objective of linking the film mismatch stress to the underlying characteristic size scales. The model is predicated on the notion that the relaxation of mismatch strain in the film is accommodated by the introduction of dislocation loops whose population, dimensions and interaction energies are controlled by the film thickness and microstructural dimensions. The model is capable of capturing the combined effects of these size scales by accounting for the interaction energies of the constrained dislocation structure, and provides quantitative predictions of the evolution of film stress during thermal excursions. The predictions of the analysis are compared with available experimental results for Polycrystalline films of face-centered cubic materials on Si substrates. It is shown that the model correctly predicts the observed influence of film thickness and grain size on stress evolution during thermal excursions. Aspects of strain hardening in thin Polycrystalline films with high dislocation densities are also discussed.
Giuseppe Iannaccone - One of the best experts on this subject based on the ideXlab platform.
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MonteCarlosimulationof electromigrationin Polycrystalline Metal stripes
2020Co-Authors: S Di Pascoli, Giuseppe IannacconeAbstract:We have developed a Monte Carlo simulator of the electromigration process in Polycrystalline Metal stripes. Stripes with different average grain size can be generated with Voronoi tesselation, and mapped onto a network of resistors. The proposed model includes the major role played by grain boundaries and by the current density redistribution within the stripe following void formation. Simulations of stripes with different grain sizes and different widths are shown, and a few expressions for the failure probability are compared on the basis of their capability of reproducing the experimental results. In addition, electromigration noise has been computed, recovering the characteristic 1/f ! (!!2) behaviour. The substantial qualitative agreement between our calculations and the experimental results is a convincing test of the capability of the model proposed to include the relevant physics.
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Simulation of electromigration noise in Polycrystalline Metal stripes
Microelectronics Reliability, 2000Co-Authors: S Di Pascoli, Giuseppe IannacconeAbstract:Abstract We have performed the Monte Carlo simulation of electromigration noise in Polycrystalline Metal stripes, based on a two-dimensional model which takes into account both the role of grain boundaries and the effect of current density redistribution in the stripe. The noise spectrum has the characteristic 1/fγ (γ≈2) behavior, and the total noise power strongly increases with increasing damage of the stripe. The results of the simulation exhibit a substantial qualitative agreement with experiments, giving confidence in the capability of our model of including the relevant physics involved in the failure process.
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Monte Carlo simulation of electromigration in Polycrystalline Metal stripes
Semiconductor Science and Technology, 2000Co-Authors: S Di Pascoli, Giuseppe IannacconeAbstract:We have developed a Monte Carlo simulator of the electromigration process in Polycrystalline Metal stripes. Stripes with different average grain size can be generated with Voronoi tesselation, and mapped onto a network of resistors. The proposed model includes the major role played by grain boundaries and by the current density redistribution within the stripe following void formation. Simulations of stripes with different grain sizes and different widths are shown, and a few expressions for the failure probability are compared on the basis of their capability of reproducing the experimental results. In addition, electromigration noise has been computed, recovering the characteristic 1/fγ (γ≈2) behaviour. The substantial qualitative agreement between our calculations and the experimental results is a convincing test of the capability of the model proposed to include the relevant physics.
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Monte Carlo simulation of electromigration in Polycrystalline Metal stripes
Proceedings of the 1999 7th International Symposium on the Physical and Failure Analysis of Integrated Circuits (Cat. No.99TH8394), 1999Co-Authors: S Di Pascoli, Giuseppe IannacconeAbstract:We have developed a Monte Carlo simulator of the electromigration process in Polycrystalline Metal stripes. Stripes with different average grain size can be generated with Voronoi tasselation, and mapped on to a network of resistors. The proposed model includes the major role played by grain boundaries and by the current density redistribution within the stripe following void formation. Simulations of stripes with different grain sizes and different widths are shown, and a few expressions for the failure probability are compared on the basis of their capability of reproducing the experimental results. In addition, electromigration noise has been computed, recovering the characteristic 1/f/sup /spl gamma//(/spl gamma//spl ap/2) behavior. The substantial qualitative agreement between our calculations and the experimental results is a convincing test of the capability of the model proposed to include the relevant physics.