Pub Date : 2012-05-22DOI: 10.1109/IWCE.2012.6242831
M. L. Gada, D. Vasileska, S. Goodnick, K. Raleva
We present simulation results for the drift velocity and mobility in silicon at various temperatures using analytical model which incorporates analytical expressions for the acoustic and optical phonon dispersions. Our simulation results for the field-dependent average drift velocity and mobility are in excellent agreement with the results that utilize the rejection technique and the experimental data for silicon for [100] crystallographic direction at different temperatures.
{"title":"Electron drift velocity and mobility calculation in bulk Si using an analytical model for the phonon dispersion","authors":"M. L. Gada, D. Vasileska, S. Goodnick, K. Raleva","doi":"10.1109/IWCE.2012.6242831","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242831","url":null,"abstract":"We present simulation results for the drift velocity and mobility in silicon at various temperatures using analytical model which incorporates analytical expressions for the acoustic and optical phonon dispersions. Our simulation results for the field-dependent average drift velocity and mobility are in excellent agreement with the results that utilize the rejection technique and the experimental data for silicon for [100] crystallographic direction at different temperatures.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124819462","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242847
I. Gamba, A. Majorana, J. A. Morales, Chi-Wang Shu
The present work is motivated by the development of a fast DG based deterministic solver for the extension of the BTE to a system of transport Boltzmann equations for full electronic multiband transport with intraband scattering mechanisms. Our proposed method allows to find scattering effects of high complexity, such as anisotropic electronic bands or full band computations, by simply using the standard routines of a suitable Monte Carlo approach only once. In this short paper, we restrict our presentation to the single band problem as it will be also valid in the multiband system as well. We present preliminary numerical tests of this method using the Kane energy band model, for a 1-D 400nm n+ - n - n+ silicon channel diode, showing moments at t = 0.5ps and t = 3.0ps.
{"title":"A fast approach to discontinuous Galerkin solvers for Boltzmann-Poisson transport systems for full electronic bands and phonon scattering","authors":"I. Gamba, A. Majorana, J. A. Morales, Chi-Wang Shu","doi":"10.1109/IWCE.2012.6242847","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242847","url":null,"abstract":"The present work is motivated by the development of a fast DG based deterministic solver for the extension of the BTE to a system of transport Boltzmann equations for full electronic multiband transport with intraband scattering mechanisms. Our proposed method allows to find scattering effects of high complexity, such as anisotropic electronic bands or full band computations, by simply using the standard routines of a suitable Monte Carlo approach only once. In this short paper, we restrict our presentation to the single band problem as it will be also valid in the multiband system as well. We present preliminary numerical tests of this method using the Kane energy band model, for a 1-D 400nm n+ - n - n+ silicon channel diode, showing moments at t = 0.5ps and t = 3.0ps.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125461054","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6401951
O. Muscato, V. Stefano
We present an extended hydrodynamic model describing the transport of electrons in the axial direction of a silicon nanowire. This model has been formulated by closing the moment system derived from the Boltzmann equations on the basis of the maximum entropy principle of Extended Thermodynamics, coupled to the Effective Mass and Poisson equations. Explicit closure relations for the high-order fluxes and the production terms are obtained without any fitting procedure, including scattering of electrons with acoustic and non polar optical phonons. By using this model, thermoelectric effects have been investigated.
{"title":"An extended hydrodynamic model for silicon nano wires","authors":"O. Muscato, V. Stefano","doi":"10.1109/IWCE.2012.6401951","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6401951","url":null,"abstract":"We present an extended hydrodynamic model describing the transport of electrons in the axial direction of a silicon nanowire. This model has been formulated by closing the moment system derived from the Boltzmann equations on the basis of the maximum entropy principle of Extended Thermodynamics, coupled to the Effective Mass and Poisson equations. Explicit closure relations for the high-order fluxes and the production terms are obtained without any fitting procedure, including scattering of electrons with acoustic and non polar optical phonons. By using this model, thermoelectric effects have been investigated.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129711816","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242836
X. Ju, Andrea Savo, Paolo Lugli, J. Kiermaier, M. Becherer, S. Breitkreutz, Doris Schmitt-Landsiedel, W. Porod, G. Csaba
Nanomagnet logic (NML) emerges as a new field of spintronics. For NML operation, strong external magnetic clocking field pulses are required. The power-efficient generation of such fields is a challenge for magnetic computing. The idea of clocking Co/Pt nanomagnets with stray field from the domain wall of a Permalloy stripe was proposed in the earlier study. Here, we present a micromagnetic investigation of Co/Pt multilayer films that strongly interact with the stray field of a Permalloy domain wall conductor. The simulated domain patterns agree well with experimental results.
{"title":"Computational study of domain-wall-induced switching of Co/Pt multilayer","authors":"X. Ju, Andrea Savo, Paolo Lugli, J. Kiermaier, M. Becherer, S. Breitkreutz, Doris Schmitt-Landsiedel, W. Porod, G. Csaba","doi":"10.1109/IWCE.2012.6242836","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242836","url":null,"abstract":"Nanomagnet logic (NML) emerges as a new field of spintronics. For NML operation, strong external magnetic clocking field pulses are required. The power-efficient generation of such fields is a challenge for magnetic computing. The idea of clocking Co/Pt nanomagnets with stray field from the domain wall of a Permalloy stripe was proposed in the earlier study. Here, we present a micromagnetic investigation of Co/Pt multilayer films that strongly interact with the stray field of a Permalloy domain wall conductor. The simulated domain patterns agree well with experimental results.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129406135","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242845
Antonio Martinez, M. Aldegunde, K. Kalna, John R. Barker
The impact of exchange and correlation (XC) in the current voltage characteristic of a gate-all-around Si nanowire transistor has been thoroughly investigated in the context of ballistic and dissipative transport. The electron transport is described using the Non Equilibrium Green Function formalism (NEGF). The XC potential is evaluated in the local density approximation. Transfer characteristics for devices with cross-section of 2.2×2.2 nm2 and 3.6×3.6 nm2 have been calculated. The calculation shows that the impact of the XC is larger for the small cross-section, producing an enhancement in the on current of close to 50%. This enhancement is gate bias dependent and has a maximum of a few hundred millivolts after the threshold voltage. The impact of the XC in the on current is comparable to the impact of scattering for the small cross-section but it is smaller at the larger cross section.
{"title":"Exchange-correlation effects in ballistic and dissipative transport in GAA Si nanowire transistors","authors":"Antonio Martinez, M. Aldegunde, K. Kalna, John R. Barker","doi":"10.1109/IWCE.2012.6242845","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242845","url":null,"abstract":"The impact of exchange and correlation (XC) in the current voltage characteristic of a gate-all-around Si nanowire transistor has been thoroughly investigated in the context of ballistic and dissipative transport. The electron transport is described using the Non Equilibrium Green Function formalism (NEGF). The XC potential is evaluated in the local density approximation. Transfer characteristics for devices with cross-section of 2.2×2.2 nm2 and 3.6×3.6 nm2 have been calculated. The calculation shows that the impact of the XC is larger for the small cross-section, producing an enhancement in the on current of close to 50%. This enhancement is gate bias dependent and has a maximum of a few hundred millivolts after the threshold voltage. The impact of the XC in the on current is comparable to the impact of scattering for the small cross-section but it is smaller at the larger cross section.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128858454","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6401950
O. Muscato, W. Wagner, V. Stefano
In this paper we present an improved version of the Electrothermal Monte Carlo method. This modification has better approximation properties due to reduced statistical fluctuations. Simulation results in 2D structures are presented.
{"title":"An efficient heat generation rate evaluation with electrothermal Monte Carlo simulations","authors":"O. Muscato, W. Wagner, V. Stefano","doi":"10.1109/IWCE.2012.6401950","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6401950","url":null,"abstract":"In this paper we present an improved version of the Electrothermal Monte Carlo method. This modification has better approximation properties due to reduced statistical fluctuations. Simulation results in 2D structures are presented.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127759429","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242850
D. Osintsev, O. Baumgartner, Z. Stanojević, V. Sverdlov, S. Selberherr
Silicon is the main element of modern charge-based electronics. Understanding the details of the spin propagation in silicon structures is elementary for novel spin-based device applications. We investigate valley splitting, surface roughness scattering, and spin relaxation matrix elements in thin silicon films by using a perturbative k·p approach. We demonstrated that applying uniaxial stress along the [110] direction considerably suppresses the intersubband spin relaxation elements.
{"title":"Reduction of surface roughness induced spin relaxation in SOI MOSFETs","authors":"D. Osintsev, O. Baumgartner, Z. Stanojević, V. Sverdlov, S. Selberherr","doi":"10.1109/IWCE.2012.6242850","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242850","url":null,"abstract":"Silicon is the main element of modern charge-based electronics. Understanding the details of the spin propagation in silicon structures is elementary for novel spin-based device applications. We investigate valley splitting, surface roughness scattering, and spin relaxation matrix elements in thin silicon films by using a perturbative k·p approach. We demonstrated that applying uniaxial stress along the [110] direction considerably suppresses the intersubband spin relaxation elements.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133942624","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242868
Ke Xu, Jun Qian, Pitamber Shukla, M. Dutta, M. Stroscio
Graphene is a very promising electronic material that has attracted vast research interests due to its unique electronic properties [1]. In this paper, a graphene-based FET-like aptamer sensor is modelled for the case of an aptamer that binds to a cocaine surrogate. Methylene-blue (MB) is a nanoscale molecule that functions as an electron donor. The graphene in these structures exhibits p-type semiconductor behavior with holes as carriers. The voltage shift caused by electron trapping on the graphene surface is observed and explained by a charge sheet capacitance model. In this work, the graphene-based FET characteristics are modelled to understand the use of this device as a sensor of molecular analytes.
{"title":"Graphene-based FET structure: Modeling FET characteristics for an aptamer-based analyte sensor","authors":"Ke Xu, Jun Qian, Pitamber Shukla, M. Dutta, M. Stroscio","doi":"10.1109/IWCE.2012.6242868","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242868","url":null,"abstract":"Graphene is a very promising electronic material that has attracted vast research interests due to its unique electronic properties [1]. In this paper, a graphene-based FET-like aptamer sensor is modelled for the case of an aptamer that binds to a cocaine surrogate. Methylene-blue (MB) is a nanoscale molecule that functions as an electron donor. The graphene in these structures exhibits p-type semiconductor behavior with holes as carriers. The voltage shift caused by electron trapping on the graphene surface is observed and explained by a charge sheet capacitance model. In this work, the graphene-based FET characteristics are modelled to understand the use of this device as a sensor of molecular analytes.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"127 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115621842","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242863
R. Soligo, D. Guerra, D. Ferry, S. Goodnick, M. Saraniti
The effects of access region scaling on the performance of millimeter-wave GaN HEMTs is investigated through nanoscale carrier dynamics description obtained by full band Cellular Monte Carlo simulation. The drain current and transconductance have shown to increase monotonically up to respectively 5500 mA/mm and 1500 mS/mm by symmetrically scaling the source to gate and gate to drain distance from 635 nm to 50 nm. The electric field distribution has been studied for the shorter access regions and it was seen to be still far from the GaN breakdown limit. The access region scaling is found to greatly improve the frequency response of the device as well: from 340 GHz up to 860 GHz. Detailed simulation of the carrier dynamics in the area under the gate showed that these improvements are due to higher transit velocity of electrons at the source end of the gate.
{"title":"Cellular Monte Carlo study lateral scaling impact of on the DC-RF performance of high-power GaN HEMTs","authors":"R. Soligo, D. Guerra, D. Ferry, S. Goodnick, M. Saraniti","doi":"10.1109/IWCE.2012.6242863","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242863","url":null,"abstract":"The effects of access region scaling on the performance of millimeter-wave GaN HEMTs is investigated through nanoscale carrier dynamics description obtained by full band Cellular Monte Carlo simulation. The drain current and transconductance have shown to increase monotonically up to respectively 5500 mA/mm and 1500 mS/mm by symmetrically scaling the source to gate and gate to drain distance from 635 nm to 50 nm. The electric field distribution has been studied for the shorter access regions and it was seen to be still far from the GaN breakdown limit. The access region scaling is found to greatly improve the frequency response of the device as well: from 340 GHz up to 860 GHz. Detailed simulation of the carrier dynamics in the area under the gate showed that these improvements are due to higher transit velocity of electrons at the source end of the gate.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125126432","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242842
A. Makarov, V. Sverdlov, S. Selberherr
We demonstrate a substantial decrease of the switching time in penta-layer MTJs with a composite free layer regardless of the size and aspect ratio of the MTJ. The composite magnetic layer consists of two half-ellipses separated by a non-magnetic spacer. We analyze the peculiarities of the magnetic dynamics of these MTJs and reveal the physical reason for the decrease of the switching time. The scaling potential based on an analysis of the thermal stability is discussed. Furthermore, we outline the method for increasing the thermal.
{"title":"MTJs with a composite free layer for high-speed spin transfer torque RAM: Micromagnetic simulations","authors":"A. Makarov, V. Sverdlov, S. Selberherr","doi":"10.1109/IWCE.2012.6242842","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242842","url":null,"abstract":"We demonstrate a substantial decrease of the switching time in penta-layer MTJs with a composite free layer regardless of the size and aspect ratio of the MTJ. The composite magnetic layer consists of two half-ellipses separated by a non-magnetic spacer. We analyze the peculiarities of the magnetic dynamics of these MTJs and reveal the physical reason for the decrease of the switching time. The scaling potential based on an analysis of the thermal stability is discussed. Furthermore, we outline the method for increasing the thermal.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131636579","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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