Pub Date : 2014-07-28DOI: 10.1109/IWCE.2014.6865811
E. Colomés, D. Marian, X. Oriols
The effect of exchange interaction on the scattering probabilities of two electrons injected simultaneously from different sources into a tunneling barrier is analyzed using time-dependent antisymmetric wave functions. Quantum noise for two electrons is calculated using this algorithm showing excellent agreement with Büttiker results for typical scenarios, while new results are obtained for more complex scenarios.
{"title":"Understandable algorithm for exchange interaction: Quantum noise in nanoelectronic devices","authors":"E. Colomés, D. Marian, X. Oriols","doi":"10.1109/IWCE.2014.6865811","DOIUrl":"https://doi.org/10.1109/IWCE.2014.6865811","url":null,"abstract":"The effect of exchange interaction on the scattering probabilities of two electrons injected simultaneously from different sources into a tunneling barrier is analyzed using time-dependent antisymmetric wave functions. Quantum noise for two electrons is calculated using this algorithm showing excellent agreement with Büttiker results for typical scenarios, while new results are obtained for more complex scenarios.","PeriodicalId":168149,"journal":{"name":"2014 International Workshop on Computational Electronics (IWCE)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128660394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-03DOI: 10.1109/IWCE.2014.6865832
M. Claus, D. Teich, S. Mothes, G. Seifert, Michael Schroter
Covalent functionalization of carbon nanotubes (CNTs) might be an option to optimize the behavior of CNT field effect transistors (FETs) [1] (despite all related technological problems). In principle, the atoms or molecules used for functionalizing are placed randomly along the CNT or they are high-ordered in decoration patterns. Here, only high-ordered functionalization patterns are studied (i) to convert metallic CNTs into semiconducting CNTs and (ii) to reduce or to increase the ambipolarity of a semiconducting CNT.
{"title":"Impact of functionalization patterns on the performance of CNTFETs","authors":"M. Claus, D. Teich, S. Mothes, G. Seifert, Michael Schroter","doi":"10.1109/IWCE.2014.6865832","DOIUrl":"https://doi.org/10.1109/IWCE.2014.6865832","url":null,"abstract":"Covalent functionalization of carbon nanotubes (CNTs) might be an option to optimize the behavior of CNT field effect transistors (FETs) [1] (despite all related technological problems). In principle, the atoms or molecules used for functionalizing are placed randomly along the CNT or they are high-ordered in decoration patterns. Here, only high-ordered functionalization patterns are studied (i) to convert metallic CNTs into semiconducting CNTs and (ii) to reduce or to increase the ambipolarity of a semiconducting CNT.","PeriodicalId":168149,"journal":{"name":"2014 International Workshop on Computational Electronics (IWCE)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127314740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-03DOI: 10.1109/IWCE.2014.6865839
S. Berrada, V. Nguyen, P. Dollfus, Q. Wilmart, G. Fève, J. Berroir, B. Plaçais
We propose a Klein tunneling transistor based on the geometrical optics of DFs. We consider the case of a prismatic active region generated by a triangular gate. In this region, total internal reflection may occur, which leads to the controllable suppression of transistor transmission. We study the transmission and the current in this device by means of non-equilibrium Green's function (NEGF) simulation.
{"title":"Graphene-based Klein tunneling transistor","authors":"S. Berrada, V. Nguyen, P. Dollfus, Q. Wilmart, G. Fève, J. Berroir, B. Plaçais","doi":"10.1109/IWCE.2014.6865839","DOIUrl":"https://doi.org/10.1109/IWCE.2014.6865839","url":null,"abstract":"We propose a Klein tunneling transistor based on the geometrical optics of DFs. We consider the case of a prismatic active region generated by a triangular gate. In this region, total internal reflection may occur, which leads to the controllable suppression of transistor transmission. We study the transmission and the current in this device by means of non-equilibrium Green's function (NEGF) simulation.","PeriodicalId":168149,"journal":{"name":"2014 International Workshop on Computational Electronics (IWCE)","volume":"73 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123427428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-03DOI: 10.1109/IWCE.2014.6865871
K. Fukuda, T. Mori, W. Mizubayashi, Y. Morita, A. Tanabe, M. Masahara, T. Yasuda, S. Migita, H. Ota
The non-local band to band tunneling model developed and implemented into the three-dimensional device simulator by the authors is evaluated for the tunnel-FET modeling focused on device geometry effects. Measured characteristics of SOI, Fin, and parallel-plate silicon tunnel FETs fabricated by the authors are compared with simulations based on the non-local model. Although each device structures have specific features in their electrical characteristics, the non-local model explains the various geometry effects very well throughout the comparisons. From these comparisons, validity and predictivity of the non-local model is ensured for the device design of tunnel FETs.
{"title":"Predictivity of the non-local BTBT model for structure dependencies of tunnel FETs","authors":"K. Fukuda, T. Mori, W. Mizubayashi, Y. Morita, A. Tanabe, M. Masahara, T. Yasuda, S. Migita, H. Ota","doi":"10.1109/IWCE.2014.6865871","DOIUrl":"https://doi.org/10.1109/IWCE.2014.6865871","url":null,"abstract":"The non-local band to band tunneling model developed and implemented into the three-dimensional device simulator by the authors is evaluated for the tunnel-FET modeling focused on device geometry effects. Measured characteristics of SOI, Fin, and parallel-plate silicon tunnel FETs fabricated by the authors are compared with simulations based on the non-local model. Although each device structures have specific features in their electrical characteristics, the non-local model explains the various geometry effects very well throughout the comparisons. From these comparisons, validity and predictivity of the non-local model is ensured for the device design of tunnel FETs.","PeriodicalId":168149,"journal":{"name":"2014 International Workshop on Computational Electronics (IWCE)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126636565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-03DOI: 10.1109/IWCE.2014.6865821
Z. Stanojević, L. Filipovic, O. Baumgartner, H. Kosina
Accurate band structure modeling is an essential ingredient in mobility modeling for any kind of semiconductor device or channel. This is particularly true for holes as the valence band of the most commonly used semiconductor materials is not even close to being parabolic. Instead, valence bands exhibit warped energy surfaces that simply cannot be approximated with parabolic valleys. To make matters worse, nanostructured channels can have large quantization energies resulting in complex, highly orientation-dependent kinetic behavior of both holes and electrons. In this work, we present an accurate and computationally efficient method for calculating channel low-feld mobilities based on a numeric band structure from a k·p model.
{"title":"Fast methods for full-band mobility calculation","authors":"Z. Stanojević, L. Filipovic, O. Baumgartner, H. Kosina","doi":"10.1109/IWCE.2014.6865821","DOIUrl":"https://doi.org/10.1109/IWCE.2014.6865821","url":null,"abstract":"Accurate band structure modeling is an essential ingredient in mobility modeling for any kind of semiconductor device or channel. This is particularly true for holes as the valence band of the most commonly used semiconductor materials is not even close to being parabolic. Instead, valence bands exhibit warped energy surfaces that simply cannot be approximated with parabolic valleys. To make matters worse, nanostructured channels can have large quantization energies resulting in complex, highly orientation-dependent kinetic behavior of both holes and electrons. In this work, we present an accurate and computationally efficient method for calculating channel low-feld mobilities based on a numeric band structure from a k·p model.","PeriodicalId":168149,"journal":{"name":"2014 International Workshop on Computational Electronics (IWCE)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115018383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-03DOI: 10.1109/IWCE.2014.6865829
Hisao Nakamura, T. Miyazaki, K. Nishio, Hisashi Shmia, H. Akinaga, Y. Asai
We performed first principles calculations of Resistive Random Access Memory (ReRAM) cell, which consists of HfO2 resistive layer and TiN electrodes, by using nonequilibrium Green's function theory combined with density functional theory (NEGF-DFT). To analyze the transport mechanism of low/high resistive (ON/OFF) states, we examined several models of the HfOx wire (filament) structures and the oxidized interfaces. We found that concentration of vacancies in a only thin filament provides sufficiently low resistance than that of the thick filament. Furthermore, the oxidized interface by scavenged oxygen ions plays an important role to distinct ON/OFF ratio in low bias voltage. In order to argue the contact effect directly, we evaluated the complex site energies based on the effective Hamiltonian formalism. Then we proposed insertion of thin metal buffer layer to control the contact effects.
{"title":"Design of ReRAM cell structure by metal buffer and contact engineering via first-principles transport calculations","authors":"Hisao Nakamura, T. Miyazaki, K. Nishio, Hisashi Shmia, H. Akinaga, Y. Asai","doi":"10.1109/IWCE.2014.6865829","DOIUrl":"https://doi.org/10.1109/IWCE.2014.6865829","url":null,"abstract":"We performed first principles calculations of Resistive Random Access Memory (ReRAM) cell, which consists of HfO2 resistive layer and TiN electrodes, by using nonequilibrium Green's function theory combined with density functional theory (NEGF-DFT). To analyze the transport mechanism of low/high resistive (ON/OFF) states, we examined several models of the HfOx wire (filament) structures and the oxidized interfaces. We found that concentration of vacancies in a only thin filament provides sufficiently low resistance than that of the thick filament. Furthermore, the oxidized interface by scavenged oxygen ions plays an important role to distinct ON/OFF ratio in low bias voltage. In order to argue the contact effect directly, we evaluated the complex site energies based on the effective Hamiltonian formalism. Then we proposed insertion of thin metal buffer layer to control the contact effects.","PeriodicalId":168149,"journal":{"name":"2014 International Workshop on Computational Electronics (IWCE)","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128004812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-03DOI: 10.1109/IWCE.2014.6865826
R. Rhyner, M. Luisier
Phonon-phonon scattering is included in an atomistic and full-band quantum transport approach where electron and phonon transport are fully coupled based on the Non-equilibrium Green's function formalism. The investigation of self-heating effects in ultra-scaled Si nanowire transistors shows that the artificial accumulation of high energy phonons caused by electron relaxations close to the drain region is softened due to the phonon decay process. As a consequence, the device current is increased in the ON-state and the effective lattice temperature is reduced.
{"title":"Influence of anharmonic phonon decay on self-heating in Si nanowire transistors","authors":"R. Rhyner, M. Luisier","doi":"10.1109/IWCE.2014.6865826","DOIUrl":"https://doi.org/10.1109/IWCE.2014.6865826","url":null,"abstract":"Phonon-phonon scattering is included in an atomistic and full-band quantum transport approach where electron and phonon transport are fully coupled based on the Non-equilibrium Green's function formalism. The investigation of self-heating effects in ultra-scaled Si nanowire transistors shows that the artificial accumulation of high energy phonons caused by electron relaxations close to the drain region is softened due to the phonon decay process. As a consequence, the device current is increased in the ON-state and the effective lattice temperature is reduced.","PeriodicalId":168149,"journal":{"name":"2014 International Workshop on Computational Electronics (IWCE)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125752586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-03DOI: 10.1109/IWCE.2014.6865873
Jose A. Morales Escalante, I. Gamba
In this paper we perform, by means of Discontinuous Galerkin (DG) Finite Element Method (FEM) based numerical solvers for Boltzmann-Poisson (BP) semiclassical models of hot electronic transport in semiconductors, a numerical study of reflective boundary conditions in the BP system, such as specular reflection, diffusive reflection, and a mixed convex combination of these reflections, and their effect on the behavior of the solution. A boundary layer effect is observed in our numerical simulations for the kinetic moments related to diffusive and mixed reflection.
{"title":"Boundary conditions effects by Discontinuous Galerkin solvers for Boltzmann-Poisson models of electron transport","authors":"Jose A. Morales Escalante, I. Gamba","doi":"10.1109/IWCE.2014.6865873","DOIUrl":"https://doi.org/10.1109/IWCE.2014.6865873","url":null,"abstract":"In this paper we perform, by means of Discontinuous Galerkin (DG) Finite Element Method (FEM) based numerical solvers for Boltzmann-Poisson (BP) semiclassical models of hot electronic transport in semiconductors, a numerical study of reflective boundary conditions in the BP system, such as specular reflection, diffusive reflection, and a mixed convex combination of these reflections, and their effect on the behavior of the solution. A boundary layer effect is observed in our numerical simulations for the kinetic moments related to diffusive and mixed reflection.","PeriodicalId":168149,"journal":{"name":"2014 International Workshop on Computational Electronics (IWCE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131156026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-03DOI: 10.1109/IWCE.2014.6865820
J. Thobel, F. Dessenne, C. Dalle
Electron transport properties of GaN-based heterostructures are investigated by means of a Monte Carlo model, which considers a large number of subbands in several valleys. Room-temperature low-field mobility consistent with experimental results is obtained provided that screening of phonon scattering is accounted for. In intrinsic heterostructures the mobility is always greater than in bulk GaN. Dislocations strongly reduce mobility at low electron density. Transport under applied field up to 300 kV/cm is also investigated. The peak velocity is found to decrease when electron density is increased.
{"title":"Monte Carlo study of low and high-field electron transport in GaN-based heterostructures","authors":"J. Thobel, F. Dessenne, C. Dalle","doi":"10.1109/IWCE.2014.6865820","DOIUrl":"https://doi.org/10.1109/IWCE.2014.6865820","url":null,"abstract":"Electron transport properties of GaN-based heterostructures are investigated by means of a Monte Carlo model, which considers a large number of subbands in several valleys. Room-temperature low-field mobility consistent with experimental results is obtained provided that screening of phonon scattering is accounted for. In intrinsic heterostructures the mobility is always greater than in bulk GaN. Dislocations strongly reduce mobility at low electron density. Transport under applied field up to 300 kV/cm is also investigated. The peak velocity is found to decrease when electron density is increased.","PeriodicalId":168149,"journal":{"name":"2014 International Workshop on Computational Electronics (IWCE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133033378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-06-03DOI: 10.1109/IWCE.2014.6865834
F. Carosella, C. Ndebeka-Bandou, R. Ferreira, G. Bastard, A. Wacker
We developed a model for the exact calculation of the absorption spectrum in disordered heterostructures allowing the understanding of the lineshape in terms of the contributions from intra-subband and inter-subband scatterings. A dopant engineering of the inter-subband lineshape is proposed.
{"title":"Absorption in disordered heterostructures: Contributions from intra- and inter-subband scattering and impact of localised states","authors":"F. Carosella, C. Ndebeka-Bandou, R. Ferreira, G. Bastard, A. Wacker","doi":"10.1109/IWCE.2014.6865834","DOIUrl":"https://doi.org/10.1109/IWCE.2014.6865834","url":null,"abstract":"We developed a model for the exact calculation of the absorption spectrum in disordered heterostructures allowing the understanding of the lineshape in terms of the contributions from intra-subband and inter-subband scatterings. A dopant engineering of the inter-subband lineshape is proposed.","PeriodicalId":168149,"journal":{"name":"2014 International Workshop on Computational Electronics (IWCE)","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127412978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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