Monte Carlo Study of the Coulomb Interaction in Nanoscale Silicon Devices

Sano, Nobuyuki

doi:10.1143/jjap.50.010108

Cited by 8 publications

(9 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Electron waves cannot maintain their coherence under such a high electric field, and their particle nature will be reinforced (see Fig. 1) [1,2]. The purpose of our study therefore is to clarify the electron characteristics in this quantum-classical crossover region.…”

Section: Introductionmentioning

confidence: 98%

Effect of Coulomb interaction on multi-electronwave packet dynamics

Shiokawa

Takada

Konabe

et al. 2013

AIP Conference Proceedings

View full text Add to dashboard Cite

We have investigated the effect of Coulomb interaction on electron transport in a one-dimensional nanoscale structure using a multi-electron wave packet approach. To study the time evolution, we numerically solve the time-dependent Hartree-Fock equation, finding that the electron wave packet dynamics strongly depends on the Coulomb interaction strength. When the Coulomb interaction is large, each electron wave packet moves separately in the presence of an electric field. With weak Coulomb interaction, however, the electron wave packets overlap, forming and moving as one collective wave packet.

show abstract

Section: Introductionmentioning

confidence: 98%

Effect of Coulomb interaction on multi-electronwave packet dynamics

Shiokawa

Takada

Konabe

et al. 2013

AIP Conference Proceedings

View full text Add to dashboard Cite

show abstract

“…Highly doped drain and source regions can further impact channel electrons, e.g., due to the build-up of mirror charges, suggesting that Coulomb interaction is a paramount ingredient in describing transport, dissipation, and equilibration in nanostructures. [2,3,6] A comprehensive understanding of electron dynamics on small time and length scales therefore is desirable to improve the device performance.Various approaches to electron transport in nanodevices have been taken so far, ranging from classical Monte Carlo and molecular dynamics methods to quantum nonequilibrium Green function calculations. [2,4,5,7,8] Here, we address the charge transport from an intermediate, semiclassical perspective, [9,10] by solving the Schrödinger equation numerically for a pair of interacting electron wave packets that propagate in a planar nanochannel.…”

mentioning

confidence: 99%

“…[2,3,6] A comprehensive understanding of electron dynamics on small time and length scales therefore is desirable to improve the device performance.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…[2,4,5,7,8] Here, we address the charge transport from an intermediate, semiclassical perspective, [9,10] by solving the Schrödinger equation numerically for a pair of interacting electron wave packets that propagate in a planar nanochannel. This approach interpolates between the classical, particle-like and the quantum, wavelike nature of electrons ( Fig.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Interacting Electron Wave Packet Dynamics in a Two-Dimensional Nanochannel

Puetter

Konabe

Hatsugai

et al. 2013

Appl. Phys. Express

View full text Add to dashboard Cite

Classical and quantum dynamics are important limits for the understanding of the transport characteristics of interacting electrons in nanodevices. Here, we apply an intermediate semiclassical approach to investigate the dynamics of two interacting electrons in a planar nanochannel as a function of Coulomb repulsion and electric field. We find that charge is mostly redistributed to the channel edges and that an electric field enhances the particle-like character of electrons. These results may have significant implications for the design and study of future nanodevices.Ideal ultrasmall logic nanodevices feature high switching speeds, low power consumption, excellent on-off current ratios and high scalability and integrability. Electron transport in ultrasmall nanodevices approaching channel lengths of approximately 10 nm, [1] however, turns out to be quasi-ballistic and intricate [2,3] due to Brownian motion (thermal noise caused by scattering and diffusion) and the discreteness of the electric charge (leading to shot noise enhanced by unscreened trapped charges). These effects give rise to significant current fluctuations at high clock speeds and low voltages, [4,5] which are detrimental to efficient device operation. This indicates that high-speed electrons in nanoscale regions cannot be described by conventional statistical frameworks such as Maxwell-Boltzmann approaches. Highly doped drain and source regions can further impact channel electrons, e.g., due to the build-up of mirror charges, suggesting that Coulomb interaction is a paramount ingredient in describing transport, dissipation, and equilibration in nanostructures. [2,3,6] A comprehensive understanding of electron dynamics on small time and length scales therefore is desirable to improve the device performance.Various approaches to electron transport in nanodevices have been taken so far, ranging from classical Monte Carlo and molecular dynamics methods to quantum nonequilibrium Green function calculations. [2,4,5,7,8] Here, we address the charge transport from an intermediate, semiclassical perspective, [9,10] by solving the Schrödinger equation numerically for a pair of interacting electron wave packets that propagate in a planar nanochannel. This approach interpolates between the classical, particle-like and the quantum, wavelike nature of electrons (Fig. 1) and approximately preserves the discreteness of the transported electron charge over appropriate (not too short) time scales. Wave packet approaches have been considered previously, but relied on strictly one-dimensional structures and/or on noninteracting electrons, or were based on approximate schemes such as the time-dependent Hartree-Fock theory. [11][12][13][14][15][16][17] Below, we study in detail the effect of Coulomb repulsion and an external electric field on wave packet propagation in a two-dimensional nanochannel. A main finding is that Coulomb repulsion redistributes the charge density to the channel walls, which makes electron transport more sensitive to perturbations at the in...

show abstract

Monte Carlo Study of Ultimate Channel Scaling in Si and In$_{\rm 0.3}$Ga$_{\rm 0.7}$As Bulk MOSFETs

Islam

Benbakhti

Kálna

2011

IEEE Trans. Nanotechnology

View full text Add to dashboard Cite

A detailed analysis of nonequilibrium electron transport in n-type Si and In 0 .3 Ga 0 .7 As MOSFETs scaled into ultimate limit of 5-nm gate length is carried out using ensemble Monte Carlo device simulations. The analysis is based on simulations of I D -V G characteristics for a template, 25-nm gate length Si MOSFET compared against previous results from various Monte Carlo device codes, and for an equivalent 25-nm gate length In 0 .3 Ga 0 .7 As MOSFET. The transistors are then laterally scaled from a gate length of 25 nm to 20, 15, 10 and 5 nm monitoring the average electron velocity, energy, and sheet density along the channel at a supply voltage of 1.0 V. A degradation of the injection velocity with the scaling of a gate/channel length is observed. While we have found a decrease in the overall electron velocity profile along the Si channel for gate lengths smaller than 10 nm and a decrease in the injection velocity from a gate length of 20 nm, the increase in the intrinsic drain current in the scaling process is continuous thanks to the increasing velocity at the drain side. However, the velocity in the InGaAs channel MOSFETs increases steadily during the scaling but the increase in the intrinsic drain current is less pronounced. This is the result of a source starvation, due to a low density of states in III-V semiconductors, which cannot provide a large enough electron sheet density in the channel. This effect is partially mitigated by the enhancement of density of states as a proportion of electrons in the source/drain transfers to upper valleys with a larger electron effective mass.

show abstract

Monte Carlo Study of the Coulomb Interaction in Nanoscale Silicon Devices

Cited by 8 publications

References 25 publications

Effect of Coulomb interaction on multi-electronwave packet dynamics

Effect of Coulomb interaction on multi-electronwave packet dynamics

Interacting Electron Wave Packet Dynamics in a Two-Dimensional Nanochannel

Monte Carlo Study of Ultimate Channel Scaling in Si and In$_{\rm 0.3}$Ga$_{\rm 0.7}$As Bulk MOSFETs

Contact Info

Product

Resources

About