The transport system (infrastructures and services) can play a strategic role for the development... more The transport system (infrastructures and services) can play a strategic role for the development of tourism in those areas that have a high level of tourist appeal but a poor accessibility. The aim of this research is to analyse the potential tourist demand for fast transfer services by helicopter, to reach attractive and not very accessible areas such as, for example, minor islands. Our study is applied to Sicily, in the south of Italy, which is characterized by cultural and naturalistic beauties as well as “weak” rail and road infrastructures and is surrounded by many nice minor islands. In particular, we refer to some very important regional tourist centres: Palermo, Taormina, which are also near to the two major Sicilian airports, and the Eolie Islands. In detail, we developed a demand model for simulating the transport mode choice behaviour of tourists moving from Palermo and Taormina to Lipari (one of the Eolie Islands) of tourists with high willingness-to- pay for travel tim...
In this paper, we have studied the impact of quantum confinement on the performance of n-type sil... more In this paper, we have studied the impact of quantum confinement on the performance of n-type silicon nanowire transistors (NWTs) for application in advanced CMOS technologies. The 3-D drift-diffusion simulations based on the density gradient approach that has been calibrated with respect to the solution of the Schrödinger equation in 2-D cross sections along the direction of the transport are presented. The simulated NWTs have cross sections and dimensional characteristics representative of the transistors expected at a 7-nm CMOS technology. Different gate lengths, cross-sectional shapes, spacer thicknesses, and doping steepness were considered. We have studied the impact of the quantum corrections on the gate capacitance, mobile charge in the channel, drain-induced barrier lowering, and subthreshold slope. The mobile charge to gate capacitance ratio, which is an indicator of the intrinsic speed of the NWTs, is also investigated. We have also estimated the optimal gate length for different NWT design conditions.
2013 IEEE International Reliability Physics Symposium (IRPS), 2013
ABSTRACT This paper presents a detailed simulation investigation of the impact of statistical var... more ABSTRACT This paper presents a detailed simulation investigation of the impact of statistical variability and 3D electrostatics on SILC distribution in nanoscale Flash memories. Considering a 1-TAT model we study the SILC statistics under stationary and dynamic retention conditions. Our results show that SILC is dispersed over the channel area due to non-uniform electrostatics in nanoscale devices. Further, the floating gate poly-silicon granularity plays a major role in determining the SILC distribution, depending on the gate polarity. Dynamic charge loss simulations highlight that the impact of 3D electrostatics is dominant over the cell-to-cell variability. Finally, we analyze the electron emission statistics on a single cell, showing that this gives rise to a lower SILC dispersion than an analytical Poisson charge loss statistics. Our results are fundamental to determine the degree of accuracy of 1D models for the post-cycling charge loss statistics simulation in nanoscale Flash memories.
2013 14th International Conference on Ultimate Integration on Silicon (ULIS), 2013
ABSTRACT A computational simulation study of oxide reliability degradation considering bias tempe... more ABSTRACT A computational simulation study of oxide reliability degradation considering bias temperature instabilities and random telegraph noise in nano-scale transistors is presented. The interplay between statistical variability, induced by random dopant fluctuations, and reliability is discussed in details, within the framework of a discrete charge trapping paradigm. The stochastic behaviour of the key reliability figures of merit is analyzed by means of both static and dynamic oxide degradation simulations.
2013 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD), 2013
Charge trapping in the gate oxide of nanoscale MOSFETs featuring an 'atomistic' channel doping pr... more Charge trapping in the gate oxide of nanoscale MOSFETs featuring an 'atomistic' channel doping profile has been revealed as a key concept to explain the RTN and BTI phenomena strongly affecting contemporary technology transistors performance. By means of a 2D Wigner function approach, in this paper we investigate the trapping of a single electron in the gate oxide of a 25nm transistor including the scattering effects due to discrete dopants in the channel. We demonstrate the ability of our simulation methodology to capture not only the quantum nature but also the transient behavior of charge-trapping and scattering phenomena.
2011 International Conference on Simulation of Semiconductor Processes and Devices, 2011
ABSTRACT A comprehensive statistical investigation of the increase in resistance associated with ... more ABSTRACT A comprehensive statistical investigation of the increase in resistance associated with charge trapping in 'atomistic' simulations is presented considering a wide range of doping densities and mesh spacing for both classical and quantum formalisms. A modified mobility model for the 'atomistic' simulations is proposed to suppress the error related to the fictitious charge trapping.
This paper examines helicopter transfer services to reach attractive and not very accessible tour... more This paper examines helicopter transfer services to reach attractive and not very accessible tourist areas, taking Sicily and its minor islands, in the South of Italy, as a case study. We investigate the viability of helicopter scheduled services for tourists moving from/to airports or doing one day tours to visit far away places. The mode choice of tourists is simulated using random utility models employing stated preference data. Heli-shuttle service is planned in terms of fleet size, frequency, fare and location pattern of heliports. The paper also analyses how a public subsidy reducing fares might change the set of feasible connections.
The creation of a sustainable transport system is the main objective of the European transport po... more The creation of a sustainable transport system is the main objective of the European transport policy. This system should encourage facilities to connect all people and should be linked with economic, social and environmental aspects of society. Current trends and future challenges will meet a growing \“accessibility” demand, highlighting concerns about the sustainability of transport. Therefore one of the priorities of transport policy is the improving of overall quality of transport, including aspects related to: personal safety, accidents and health hazards reduction, protection of passengers rights and of accessibility to remote areas. This paper is dedicated to sustainable development, with particular attention to urban transport and to daily mobility of citizens. It is important to analyze all the aspects that make it possible to clarify a definition of \“sustainable transport”. Their analysis has to be related to the individuation of a set of indicators that simultaneously ta...
Il sistema dei trasporti può svolgere un ruolo strategico per lo sviluppo del turismo in quelle a... more Il sistema dei trasporti può svolgere un ruolo strategico per lo sviluppo del turismo in quelle aree che possiedono un elevato livello di attrattività turistica, ma una scarsa accessibilità. Lo scopo di questo studio è quello di formulare strategie e interventi di natura infrastrutturale e organizzativa per innalzare l’accessibilità di zone dotate di una spiccata attrattività turistica. Questo studio è stato sviluppato riguardo al territorio siciliano, caratterizzato da un prezioso patrimonio culturale e naturalistico. Tra gli interventi si è studiata l’ipotesi di??proporre servizi elicotteristici di linea tra alcune località turistiche di particolare pregio come le isole minori.??Il costo elevato del trasporto elicotteristico ha portato a considerare quali potenziali utenti del servizio solamente i visitatori aventi un’elevata disponibilità a pagare per ottenere un consistente risparmio sul tempo di viaggio. Sulla base delle simulazioni effettuate tramite modelli di utilità casuale...
ABSTRACT In this paper we illustrate how the predictive Technology Computer Aided Design (TCAD) p... more ABSTRACT In this paper we illustrate how the predictive Technology Computer Aided Design (TCAD) process device simulation can be used to evaluate process, statistical, and time-dependent variability at the early stage of the development of new technology. This is critically important for the delivery of accurate early Process Design Kits, including process variability, statistical variability, time-dependent variability (degradation) and their interactions and correlations. This is also critical to the TCAD-based Design-Technology Co-Optimisation (DTCO). To accomplish this task, the fast, large area Coventor virtual fabrication platform SEMulator3D was integrated in the GoldStandradSimulations TCAD-based DTCO tool chain. Published data for Intel 22-nm FinFET technology are used to illustrate and validate the results of the TCAD process and device simulation, the compact model extraction, and the statistical circuit simulation.
Background and Purpose-Neuronal Na ϩ /Ca 2ϩ exchanger plays a relevant role in maintaining intrac... more Background and Purpose-Neuronal Na ϩ /Ca 2ϩ exchanger plays a relevant role in maintaining intracellular Ca 2ϩ and Na ϩ levels under physiological and pathological conditions. However, the role of this exchanger in excitotoxicity and ischemia-induced neuronal injury is still controversial and has never been studied in the same neuronal subtypes. Methods-We investigated the effects of bepridil and 3Ј,4Ј-dichlorobenzamil (DCB), 2 blockers of the Na ϩ /Ca 2ϩ exchanger, in rat striatal spiny neurons by utilizing intracellular recordings in brain slice preparations to compare the action of these drugs on the membrane potential changes induced either by oxygen and glucose deprivation (OGD) or by excitatory amino acids (EAAs). Results-Bepridil (3 to 100 mol/L) and DCB (3 to 100 mol/L) caused a dose-dependent enhancement of the OGD-induced depolarization measured in striatal neurons. The EC 50 values for these effects were 31 mol/L and 29 mol/L, respectively. At these concentrations neither bepridil nor DCB altered the resting membrane properties of the recorded cells (membrane potential, input resistance, and current-voltage relationship). The effects of bepridil and DCB on the OGD-induced membrane depolarization persisted in the presence of D-2-amino-5-phosphonovalerate (50 mol/L) plus 6-cyano-7-nitroquinoxaline-2,3-dione (20 mol/L), which suggests that they were not mediated by an enhanced release of EAAs. Neither tetrodotoxin (1 mol/L) nor nifedipine (10 mol/L) affect the actions of these 2 blockers of the Na ϩ /Ca 2ϩ exchanger, which indicates that voltage-dependent Na ϩ channels and L-type Ca 2ϩ channels were not involved in the enhancement of the OGD-induced depolarization. Conversely, the OGD-induced membrane depolarization was not altered by 5-(N,N-hexamethylene) amiloride (1 to 3 mol/L), an inhibitor of the Na ϩ /H ϩ exchanger, which suggests that this antiporter did not play a prominent role in the OGD-induced membrane depolarization recorded from striatal neurons. Bepridil (3 to 100 mol/L) and DCB (3 to 100 mol/L) did not modify the amplitude of the excitatory postsynaptic potentials evoked by cortical stimulation. Moreover, these blockers did not affect membrane depolarizations caused by brief applications of glutamate (0.3 to 1 mmol/L), AMPA (0.3 to 1 mol/L), and NMDA (10 to 30 mol/L). Conclusions-These results provide pharmacological evidence that the activation of the Na ϩ /Ca 2ϩ exchanger exerts a protective role during the early phase of OGD in striatal neurons, although it does not shape the amplitude and the duration of the electrophysiological responses of these cells to EAA. (Stroke. 1999;30:1687-1693.)
2012 Proceedings of the European Solid-State Device Research Conference (ESSDERC), 2012
ABSTRACT We present a thorough statistical investigation of random telegraph noise (RTN) and bias... more ABSTRACT We present a thorough statistical investigation of random telegraph noise (RTN) and bias temperature instabilities (BTI) in nanoscale MOSFETs. By means of 3D TCAD 'atomistic' simulations, we evaluate the statistical distribution in capture/emission time constants and in threshold voltage shift (ΔVT) amplitudes due to single trapped charge, comparing its impact on RTN and BTI. Our analysis shows that, neglecting any impact of charge trapping on trans-characteristic degradation, the individual BTI ΔVT steps are distributed identically as the RTN ΔVT steps. However, the individual traps in a device cannot be considered as uncorrelated sources of noise because their mutual interaction is fundamental in determining the dispersion of capture/emission time constants in BTI simulation. These results are of utmost importance for profoundly understanding the differences and similarities in the statistical behavior of RTN and BTI phenomena.
2008 IEEE International Electron Devices Meeting, 2008
We present a new physics-based model able to reproduce the program/erase transients in TANOS memo... more We present a new physics-based model able to reproduce the program/erase transients in TANOS memories, accurately describing the charge trapping/detrapping dynamics in the nitride layer. Modeling results are extensively validated against a large number of experimental data taken on samples with different gate stack compositions, considering a quite extended range of program/erase voltages and times. The good agreement between experimental
In neurons, as in other excitable cells, mitochondria extrude Ca(2+) ions from their matrix in ex... more In neurons, as in other excitable cells, mitochondria extrude Ca(2+) ions from their matrix in exchange with cytosolic Na(+) ions. This exchange is mediated by a specific transporter located in the inner mitochondrial membrane, the mitochondrial Na(+)/Ca(2+) exchanger (NCX(mito)). The stoichiometry of NCX(mito)-operated Na(+)/Ca(2+) exchange has been the subject of a long controversy, but evidence of an electrogenic 3 Na(+)/1 Ca(2+) exchange is increasing. Although the molecular identity of NCX(mito) is still undetermined, data obtained in our laboratory suggest that besides the long-sought and as yet unfound mitochondrial-specific NCX, the three isoforms of plasmamembrane NCX can contribute to NCX(mito) in neurons and astrocytes. NCX(mito) has a role in controlling neuronal Ca(2+) homeostasis and neuronal bioenergetics. Indeed, by cycling the Ca(2+) ions captured by mitochondria back to the cytosol, NCX(mito) determines a shoulder in neuronal [Ca(2+)](c) responses to neurotransmitt...
2011 3rd IEEE International Memory Workshop (IMW), 2011
... AbstractIn this paper we present a detailed simulation analysis of the impact of the substra... more ... AbstractIn this paper we present a detailed simulation analysis of the impact of the substrate doping profile on Random Telegraph Noise (RTN) instabilities in deca-nanometer Floating Gate Flash memories. Following a Monte Carlo procedure, the statistical distribution of the ...
ABSTRACT This paper presents a comprehensive numerical modeling for the threshold-voltage transie... more ABSTRACT This paper presents a comprehensive numerical modeling for the threshold-voltage transients of nitride-based memory devices during programming, erasing and data retention. The developed numerical tool self-consistently solves the Poisson, continuity and trapping equations in the nitride layer using a drift-diffusion formalism. The continuity equation has been discretized using the Scharfetter–Gummel scheme and a modified Gummel-map has been optimized to ensure fully convergence of the equations. The numerical model is able to describe the memory device operation for different gate bias regimes, therefore addressing both the program/erase and the retention conditions. Finally, numerical results are shown to carefully reproduce experimental data on template devices with different gate stack compositions, validating the physical assumptions and making the model a valuable tool for nitride memories investigation and design.
2013 IEEE International Reliability Physics Symposium (IRPS), 2013
ABSTRACT In this paper we present a reliability simulation framework from atomistic simulations u... more ABSTRACT In this paper we present a reliability simulation framework from atomistic simulations up to circuit simulations, including traps interactions with variability sources. Trapping and detrapping dynamics are reproduced by a kinetic Monte-Carlo engine, which enables oxide degradation simulations such as BTI and RTN phenomenon on large ensembles of atomistic devices. Based on these results compact models are extracted and circuit lifetime projections are derived.
ABSTRACT In this paper, we compare results from atomistic and continuous simulation of decananome... more ABSTRACT In this paper, we compare results from atomistic and continuous simulation of decananometer scale CMOS transistors. We study the behavior of important figures of merit, including threshold voltage, subthreshold slope, OFF-current, and ON-current. We provide physical explanation for the origin of the discrepancies between the averaged values obtained from the statistical simulations and the results from the continuous doping simulation. Based on our analysis, we clearly demonstrate that there are increasing errors in the doping distributions when device TCAD simulations are calibrated using continuous doping profiles. This questions the use of continuous doping profiles in the routine calibration and TCAD-based optimization of decananometer scale CMOS transistors.
The transport system (infrastructures and services) can play a strategic role for the development... more The transport system (infrastructures and services) can play a strategic role for the development of tourism in those areas that have a high level of tourist appeal but a poor accessibility. The aim of this research is to analyse the potential tourist demand for fast transfer services by helicopter, to reach attractive and not very accessible areas such as, for example, minor islands. Our study is applied to Sicily, in the south of Italy, which is characterized by cultural and naturalistic beauties as well as “weak” rail and road infrastructures and is surrounded by many nice minor islands. In particular, we refer to some very important regional tourist centres: Palermo, Taormina, which are also near to the two major Sicilian airports, and the Eolie Islands. In detail, we developed a demand model for simulating the transport mode choice behaviour of tourists moving from Palermo and Taormina to Lipari (one of the Eolie Islands) of tourists with high willingness-to- pay for travel tim...
In this paper, we have studied the impact of quantum confinement on the performance of n-type sil... more In this paper, we have studied the impact of quantum confinement on the performance of n-type silicon nanowire transistors (NWTs) for application in advanced CMOS technologies. The 3-D drift-diffusion simulations based on the density gradient approach that has been calibrated with respect to the solution of the Schrödinger equation in 2-D cross sections along the direction of the transport are presented. The simulated NWTs have cross sections and dimensional characteristics representative of the transistors expected at a 7-nm CMOS technology. Different gate lengths, cross-sectional shapes, spacer thicknesses, and doping steepness were considered. We have studied the impact of the quantum corrections on the gate capacitance, mobile charge in the channel, drain-induced barrier lowering, and subthreshold slope. The mobile charge to gate capacitance ratio, which is an indicator of the intrinsic speed of the NWTs, is also investigated. We have also estimated the optimal gate length for different NWT design conditions.
2013 IEEE International Reliability Physics Symposium (IRPS), 2013
ABSTRACT This paper presents a detailed simulation investigation of the impact of statistical var... more ABSTRACT This paper presents a detailed simulation investigation of the impact of statistical variability and 3D electrostatics on SILC distribution in nanoscale Flash memories. Considering a 1-TAT model we study the SILC statistics under stationary and dynamic retention conditions. Our results show that SILC is dispersed over the channel area due to non-uniform electrostatics in nanoscale devices. Further, the floating gate poly-silicon granularity plays a major role in determining the SILC distribution, depending on the gate polarity. Dynamic charge loss simulations highlight that the impact of 3D electrostatics is dominant over the cell-to-cell variability. Finally, we analyze the electron emission statistics on a single cell, showing that this gives rise to a lower SILC dispersion than an analytical Poisson charge loss statistics. Our results are fundamental to determine the degree of accuracy of 1D models for the post-cycling charge loss statistics simulation in nanoscale Flash memories.
2013 14th International Conference on Ultimate Integration on Silicon (ULIS), 2013
ABSTRACT A computational simulation study of oxide reliability degradation considering bias tempe... more ABSTRACT A computational simulation study of oxide reliability degradation considering bias temperature instabilities and random telegraph noise in nano-scale transistors is presented. The interplay between statistical variability, induced by random dopant fluctuations, and reliability is discussed in details, within the framework of a discrete charge trapping paradigm. The stochastic behaviour of the key reliability figures of merit is analyzed by means of both static and dynamic oxide degradation simulations.
2013 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD), 2013
Charge trapping in the gate oxide of nanoscale MOSFETs featuring an 'atomistic' channel doping pr... more Charge trapping in the gate oxide of nanoscale MOSFETs featuring an 'atomistic' channel doping profile has been revealed as a key concept to explain the RTN and BTI phenomena strongly affecting contemporary technology transistors performance. By means of a 2D Wigner function approach, in this paper we investigate the trapping of a single electron in the gate oxide of a 25nm transistor including the scattering effects due to discrete dopants in the channel. We demonstrate the ability of our simulation methodology to capture not only the quantum nature but also the transient behavior of charge-trapping and scattering phenomena.
2011 International Conference on Simulation of Semiconductor Processes and Devices, 2011
ABSTRACT A comprehensive statistical investigation of the increase in resistance associated with ... more ABSTRACT A comprehensive statistical investigation of the increase in resistance associated with charge trapping in 'atomistic' simulations is presented considering a wide range of doping densities and mesh spacing for both classical and quantum formalisms. A modified mobility model for the 'atomistic' simulations is proposed to suppress the error related to the fictitious charge trapping.
This paper examines helicopter transfer services to reach attractive and not very accessible tour... more This paper examines helicopter transfer services to reach attractive and not very accessible tourist areas, taking Sicily and its minor islands, in the South of Italy, as a case study. We investigate the viability of helicopter scheduled services for tourists moving from/to airports or doing one day tours to visit far away places. The mode choice of tourists is simulated using random utility models employing stated preference data. Heli-shuttle service is planned in terms of fleet size, frequency, fare and location pattern of heliports. The paper also analyses how a public subsidy reducing fares might change the set of feasible connections.
The creation of a sustainable transport system is the main objective of the European transport po... more The creation of a sustainable transport system is the main objective of the European transport policy. This system should encourage facilities to connect all people and should be linked with economic, social and environmental aspects of society. Current trends and future challenges will meet a growing \“accessibility” demand, highlighting concerns about the sustainability of transport. Therefore one of the priorities of transport policy is the improving of overall quality of transport, including aspects related to: personal safety, accidents and health hazards reduction, protection of passengers rights and of accessibility to remote areas. This paper is dedicated to sustainable development, with particular attention to urban transport and to daily mobility of citizens. It is important to analyze all the aspects that make it possible to clarify a definition of \“sustainable transport”. Their analysis has to be related to the individuation of a set of indicators that simultaneously ta...
Il sistema dei trasporti può svolgere un ruolo strategico per lo sviluppo del turismo in quelle a... more Il sistema dei trasporti può svolgere un ruolo strategico per lo sviluppo del turismo in quelle aree che possiedono un elevato livello di attrattività turistica, ma una scarsa accessibilità. Lo scopo di questo studio è quello di formulare strategie e interventi di natura infrastrutturale e organizzativa per innalzare l’accessibilità di zone dotate di una spiccata attrattività turistica. Questo studio è stato sviluppato riguardo al territorio siciliano, caratterizzato da un prezioso patrimonio culturale e naturalistico. Tra gli interventi si è studiata l’ipotesi di??proporre servizi elicotteristici di linea tra alcune località turistiche di particolare pregio come le isole minori.??Il costo elevato del trasporto elicotteristico ha portato a considerare quali potenziali utenti del servizio solamente i visitatori aventi un’elevata disponibilità a pagare per ottenere un consistente risparmio sul tempo di viaggio. Sulla base delle simulazioni effettuate tramite modelli di utilità casuale...
ABSTRACT In this paper we illustrate how the predictive Technology Computer Aided Design (TCAD) p... more ABSTRACT In this paper we illustrate how the predictive Technology Computer Aided Design (TCAD) process device simulation can be used to evaluate process, statistical, and time-dependent variability at the early stage of the development of new technology. This is critically important for the delivery of accurate early Process Design Kits, including process variability, statistical variability, time-dependent variability (degradation) and their interactions and correlations. This is also critical to the TCAD-based Design-Technology Co-Optimisation (DTCO). To accomplish this task, the fast, large area Coventor virtual fabrication platform SEMulator3D was integrated in the GoldStandradSimulations TCAD-based DTCO tool chain. Published data for Intel 22-nm FinFET technology are used to illustrate and validate the results of the TCAD process and device simulation, the compact model extraction, and the statistical circuit simulation.
Background and Purpose-Neuronal Na ϩ /Ca 2ϩ exchanger plays a relevant role in maintaining intrac... more Background and Purpose-Neuronal Na ϩ /Ca 2ϩ exchanger plays a relevant role in maintaining intracellular Ca 2ϩ and Na ϩ levels under physiological and pathological conditions. However, the role of this exchanger in excitotoxicity and ischemia-induced neuronal injury is still controversial and has never been studied in the same neuronal subtypes. Methods-We investigated the effects of bepridil and 3Ј,4Ј-dichlorobenzamil (DCB), 2 blockers of the Na ϩ /Ca 2ϩ exchanger, in rat striatal spiny neurons by utilizing intracellular recordings in brain slice preparations to compare the action of these drugs on the membrane potential changes induced either by oxygen and glucose deprivation (OGD) or by excitatory amino acids (EAAs). Results-Bepridil (3 to 100 mol/L) and DCB (3 to 100 mol/L) caused a dose-dependent enhancement of the OGD-induced depolarization measured in striatal neurons. The EC 50 values for these effects were 31 mol/L and 29 mol/L, respectively. At these concentrations neither bepridil nor DCB altered the resting membrane properties of the recorded cells (membrane potential, input resistance, and current-voltage relationship). The effects of bepridil and DCB on the OGD-induced membrane depolarization persisted in the presence of D-2-amino-5-phosphonovalerate (50 mol/L) plus 6-cyano-7-nitroquinoxaline-2,3-dione (20 mol/L), which suggests that they were not mediated by an enhanced release of EAAs. Neither tetrodotoxin (1 mol/L) nor nifedipine (10 mol/L) affect the actions of these 2 blockers of the Na ϩ /Ca 2ϩ exchanger, which indicates that voltage-dependent Na ϩ channels and L-type Ca 2ϩ channels were not involved in the enhancement of the OGD-induced depolarization. Conversely, the OGD-induced membrane depolarization was not altered by 5-(N,N-hexamethylene) amiloride (1 to 3 mol/L), an inhibitor of the Na ϩ /H ϩ exchanger, which suggests that this antiporter did not play a prominent role in the OGD-induced membrane depolarization recorded from striatal neurons. Bepridil (3 to 100 mol/L) and DCB (3 to 100 mol/L) did not modify the amplitude of the excitatory postsynaptic potentials evoked by cortical stimulation. Moreover, these blockers did not affect membrane depolarizations caused by brief applications of glutamate (0.3 to 1 mmol/L), AMPA (0.3 to 1 mol/L), and NMDA (10 to 30 mol/L). Conclusions-These results provide pharmacological evidence that the activation of the Na ϩ /Ca 2ϩ exchanger exerts a protective role during the early phase of OGD in striatal neurons, although it does not shape the amplitude and the duration of the electrophysiological responses of these cells to EAA. (Stroke. 1999;30:1687-1693.)
2012 Proceedings of the European Solid-State Device Research Conference (ESSDERC), 2012
ABSTRACT We present a thorough statistical investigation of random telegraph noise (RTN) and bias... more ABSTRACT We present a thorough statistical investigation of random telegraph noise (RTN) and bias temperature instabilities (BTI) in nanoscale MOSFETs. By means of 3D TCAD 'atomistic' simulations, we evaluate the statistical distribution in capture/emission time constants and in threshold voltage shift (ΔVT) amplitudes due to single trapped charge, comparing its impact on RTN and BTI. Our analysis shows that, neglecting any impact of charge trapping on trans-characteristic degradation, the individual BTI ΔVT steps are distributed identically as the RTN ΔVT steps. However, the individual traps in a device cannot be considered as uncorrelated sources of noise because their mutual interaction is fundamental in determining the dispersion of capture/emission time constants in BTI simulation. These results are of utmost importance for profoundly understanding the differences and similarities in the statistical behavior of RTN and BTI phenomena.
2008 IEEE International Electron Devices Meeting, 2008
We present a new physics-based model able to reproduce the program/erase transients in TANOS memo... more We present a new physics-based model able to reproduce the program/erase transients in TANOS memories, accurately describing the charge trapping/detrapping dynamics in the nitride layer. Modeling results are extensively validated against a large number of experimental data taken on samples with different gate stack compositions, considering a quite extended range of program/erase voltages and times. The good agreement between experimental
In neurons, as in other excitable cells, mitochondria extrude Ca(2+) ions from their matrix in ex... more In neurons, as in other excitable cells, mitochondria extrude Ca(2+) ions from their matrix in exchange with cytosolic Na(+) ions. This exchange is mediated by a specific transporter located in the inner mitochondrial membrane, the mitochondrial Na(+)/Ca(2+) exchanger (NCX(mito)). The stoichiometry of NCX(mito)-operated Na(+)/Ca(2+) exchange has been the subject of a long controversy, but evidence of an electrogenic 3 Na(+)/1 Ca(2+) exchange is increasing. Although the molecular identity of NCX(mito) is still undetermined, data obtained in our laboratory suggest that besides the long-sought and as yet unfound mitochondrial-specific NCX, the three isoforms of plasmamembrane NCX can contribute to NCX(mito) in neurons and astrocytes. NCX(mito) has a role in controlling neuronal Ca(2+) homeostasis and neuronal bioenergetics. Indeed, by cycling the Ca(2+) ions captured by mitochondria back to the cytosol, NCX(mito) determines a shoulder in neuronal [Ca(2+)](c) responses to neurotransmitt...
2011 3rd IEEE International Memory Workshop (IMW), 2011
... AbstractIn this paper we present a detailed simulation analysis of the impact of the substra... more ... AbstractIn this paper we present a detailed simulation analysis of the impact of the substrate doping profile on Random Telegraph Noise (RTN) instabilities in deca-nanometer Floating Gate Flash memories. Following a Monte Carlo procedure, the statistical distribution of the ...
ABSTRACT This paper presents a comprehensive numerical modeling for the threshold-voltage transie... more ABSTRACT This paper presents a comprehensive numerical modeling for the threshold-voltage transients of nitride-based memory devices during programming, erasing and data retention. The developed numerical tool self-consistently solves the Poisson, continuity and trapping equations in the nitride layer using a drift-diffusion formalism. The continuity equation has been discretized using the Scharfetter–Gummel scheme and a modified Gummel-map has been optimized to ensure fully convergence of the equations. The numerical model is able to describe the memory device operation for different gate bias regimes, therefore addressing both the program/erase and the retention conditions. Finally, numerical results are shown to carefully reproduce experimental data on template devices with different gate stack compositions, validating the physical assumptions and making the model a valuable tool for nitride memories investigation and design.
2013 IEEE International Reliability Physics Symposium (IRPS), 2013
ABSTRACT In this paper we present a reliability simulation framework from atomistic simulations u... more ABSTRACT In this paper we present a reliability simulation framework from atomistic simulations up to circuit simulations, including traps interactions with variability sources. Trapping and detrapping dynamics are reproduced by a kinetic Monte-Carlo engine, which enables oxide degradation simulations such as BTI and RTN phenomenon on large ensembles of atomistic devices. Based on these results compact models are extracted and circuit lifetime projections are derived.
ABSTRACT In this paper, we compare results from atomistic and continuous simulation of decananome... more ABSTRACT In this paper, we compare results from atomistic and continuous simulation of decananometer scale CMOS transistors. We study the behavior of important figures of merit, including threshold voltage, subthreshold slope, OFF-current, and ON-current. We provide physical explanation for the origin of the discrepancies between the averaged values obtained from the statistical simulations and the results from the continuous doping simulation. Based on our analysis, we clearly demonstrate that there are increasing errors in the doping distributions when device TCAD simulations are calibrated using continuous doping profiles. This questions the use of continuous doping profiles in the routine calibration and TCAD-based optimization of decananometer scale CMOS transistors.
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Papers by Salvatore Amoroso