COMPARISON OF TRANSIENT BALLISTIC ELECTRON TRANSPORT IN BULK WURTZITE PHASE 6H-SiC and GaN

An ensemble Monte Carlo simulation is used to compare bulk electron ballistic transport in 6H - SiC and GaN materials. Electronic states within the conduction band valleys at Γ1, U, M, Γ3, and K are represented by nonparabolic ellipsoidal valleys centered on important symmetry points of the Brillouin zone. The large optical phonon energy (~120 meV) and the large intervalley energy separation between the Γ and satellite conduction band valleys suggest an increasing role for ballistic electron effects in 6H - SiC , especially when compared with most III-V semiconductors such as GaAs . Transient velocity overshoot has been simulated, with the sudden application of fields up to ~5×107 Vm -1, appropriate to the gate-drain fields expected within an operational field effect transistor. A peak-saturation drift velocity ratio of 2:1 is predicted for 6H - SiC material while that for GaN is 4:1. The electron drift velocity relaxes to the saturation value of ~2×105 ms -1 within 3 ps, for both crystal structures. The transient velocity overshoot characteristics are in fair agreement with other recent calculations.

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Velocity Overshoot And Ballistic Electron Transport In Wurtzite Indium Nitride

MRS Proceedings ◽

10.1557/proc-482-821 ◽

1997 ◽

Vol 482 ◽

Cited By ~ 6

Author(s):

B. E. Foutz ◽

S. K. O'leary ◽

M. S. Shur ◽

L. F. Eastman ◽

U. V. Bhapkar

Keyword(s):

Drift Velocity ◽

Field Effect Transistors ◽

Indium Nitride ◽

Ballistic Transport ◽

Velocity Overshoot ◽

Ensemble Monte Carlo ◽

Ballistic Electron ◽

Low Field ◽

Ballistic Electron Transport ◽

Low Field Mobility

AbstractUsing an ensemble Monte Carlo approach, ballistic transport and velocity overshoot effects are examined in InN and compared with those in GaN and GaAs. It is found that the peak overshoot velocity is in general greater than both GaN and GaAs. Furthermore, the velocity overshoot in InN occurs over distances in excess of 0.4 μm, which is comparable to GaAs but is significantly longer than the overshoot in GaN. These strong overshoot effects, combined with a high peak drift velocity, large low-field mobility, and large saturation drift velocity, should allow InN based field effect transistors to outperform their GaN and GaAs based counterparts.

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COMPARISON OF HIGH FIELD STEADY STATE AND TRANSIENT ELECTRON TRANSPORT IN WURTZITE GaN, AlN AND InN

Modern Physics Letters B ◽

10.1142/s0217984907014103 ◽

2007 ◽

Vol 21 (25) ◽

pp. 1715-1721 ◽

Cited By ~ 7

Author(s):

H. ARABSHAHI ◽

M. R. BENAM ◽

B. SALAHI ◽

M. GHOLIZADEH

Keyword(s):

Steady State ◽

Electron Transport ◽

Critical Field ◽

Electron Velocity ◽

Wurtzite Phase ◽

Velocity Overshoot ◽

Ensemble Monte Carlo ◽

A Value ◽

Transient Velocity ◽

Effect Transistor

An ensemble Monte Carlo simulation is used to compare bulk electron transport in wurtzite phase GaN , AlN and InN materials. Electronic states within the conduction band valleys at the Γ1, U, M, Γ3 and K are represented by non-parabolic ellipsoidal valleys centered on important symmetry points of the Brillouin zone. For all materials, it is found that electron velocity overshoot only occurs when the electric field is increased to a value above a certain critical field, unique to each material. This critical field is strongly dependent on the material parameters. Transient velocity overshoot has also been simulated, with the sudden application of fields up to ~5 × 107 Vm -1, appropriate to the gate-drain fields expected within an operational field effect transistor. The electron drift velocity relaxes to the saturation value of ~1.4 × 105 ms -1 within 4 ps, for all crystal structures. The steady state and transient velocity overshoot characteristics are in fair agreement with other recent calculations.

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Analyses of Ballistic Electron Transport in Nanocrystalline Porous Silicon

MRS Proceedings ◽

10.1557/proc-638-f3.3.1 ◽

2000 ◽

Vol 638 ◽

Cited By ~ 1

Author(s):

Akira Kojima ◽

Xia Sheng ◽

Nobuyoshi Koshida

Keyword(s):

Electron Transport ◽

Porous Silicon ◽

Energy Distribution ◽

Electron Emission ◽

Ballistic Transport ◽

Peak Position ◽

Ballistic Electron ◽

Ballistic Electron Transport ◽

Technological Potential ◽

Nanocrystalline Layer

AbstractThe characteristics of ballistic electron transport in porous silicon (PS) are investigated in terms of the electron emission from PS diodes and the energy distribution of emitted electrons. The energy distributions show a behavior of ballistic electron emission that is quite different with the Maxwellian distribution. This is clearly observed at low temperatures below 150 K where the electrical conduction in PS is dominated by the tunneling mode. At 100 K, the peak position of distribution curve becomes more close to the energy corresponding to the energy gain expected from ballistic transport without any scattering losses. The simulated energy distribution suggests that the electrons having higher energies in a non-equilibrium state travel ballistically in PS via field-induced tunneling process. These results support that electrons can travel ballistically in nanocrystalline layer under a high electric field. The observed ballistic transport indicates the further technological potential of silicon nanocrystallites.

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Observation of Quantized Ballistic Transport in Amorphous Silicon Memory Structures

MRS Proceedings ◽

10.1557/proc-192-347 ◽

1990 ◽

Vol 192 ◽

Cited By ~ 2

Author(s):

J. Hajto ◽

M.J. Rose ◽

P.G. LeComber ◽

A.E. Owen ◽

A.J. Snell

Keyword(s):

Magnetic Field ◽

Amorphous Silicon ◽

High Temperatures ◽

Ballistic Transport ◽

Conducting Channel ◽

One Dimensional ◽

Ballistic Electron ◽

Ballistic Electron Transport ◽

Spin Degeneracy ◽

Memory Structures

ABSTRACTWe present experimental results showing that the ON state of amorphous silicon memory structures exhibits ballistic electron transport associated with a quantised resistance, h/2ie2, where i is the number of occupied one dimensional conducting channels (sub-bands) and the spin degeneracy is two (in the case when no magnetic field is applied). Conduction in the memory ON state is restricted to a narrow conducting channel through which the electrons can travel ballistically i.e. no collisions occur. As the applied voltage is increased, the width of the conducting channel is broadened. This results in additional conducting channels (sub-bands) passing through the Fermi energy and consequently the resistance drops by quantised values. In the presence of a magnetic field additional steps occur corresponding to the split levels at values of h/2(i + ½)e2. A particular feature of this quantised resistance is that the effect can be observed at relatively high temperatures effect can be observed at relatively high temperatures (from 4.2 K up to ∼190K).

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Contribution of D-Band Electrons to Ballistic Electron Transport and Interfacial Scattering During Electron-Phonon Nonequilibrium in Thin Metal Films

Volume 2: Theory and Fundamental Research; Aerospace Heat Transfer; Gas Turbine Heat Transfer; Computational Heat Transfer ◽

10.1115/ht2009-88270 ◽

2009 ◽

Cited By ~ 2

Author(s):

Patrick E. Hopkins

Keyword(s):

Thin Films ◽

Energy Transfer ◽

Electron Transport ◽

Conduction Band ◽

Metal Films ◽

Electronic Excitations ◽

Thin Metal Films ◽

Ballistic Electron ◽

Ballistic Electron Transport ◽

Interface Scattering

Electron-interface scattering during electron-phonon nonequilibrium in thin films creates another pathway for electron system energy loss as characteristic lengths of thin films continue to decrease. As power densities in nanodevices increase, excitations of electrons from sub-conduction-band energy levels will become more probable. These sub-conduction-band electronic excitations significantly affect the material’s thermophysical properties. In this work, the effects of d-band electronic excitations are considered in electron energy transfer processes in thin metal films. In thin films with thicknesses less than the electron mean free path, ballistic electron transport leads to electron-interface scattering. The ballistic component of electron transport, leading to electron-interface scattering, is studied by a ballistic-diffusive approximation of the Boltzmann Transport Equation. The effects of d-band excitations on electron-interface energy transfer is analyzed during electron-phonon nonequilibrium after short pulsed laser heating in thin films.

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MONTE CARLO MODELING OF HOT ELECTRON TRANSPORT IN BULK AlAs, AlGaAs AND GaAs AT ROOM TEMPERATURE

Modern Physics Letters B ◽

10.1142/s0217984908016376 ◽

2008 ◽

Vol 22 (18) ◽

pp. 1777-1784 ◽

Cited By ~ 1

Author(s):

H. ARABSHAHI ◽

M. R. KHALVATI ◽

M. REZAEE ROKN-ABADI

Keyword(s):

Monte Carlo ◽

Drift Velocity ◽

Critical Field ◽

Electron Drift Velocity ◽

Electron Velocity ◽

Electron Drift ◽

Hot Electron ◽

Velocity Overshoot ◽

Transient Velocity ◽

Hot Electron Transport

The results of an ensemble Monte Carlo simulation of electron drift velocity response on the application field in bulk AlAs , AlGaAs and GaAs are presented. All dominant scattering mechanisms in the structure considered have been taken into account. For all materials, it is found that electron velocity overshoot only occurs when the electric field is increased to a value above a certain critical field, unique to each material. This critical field is strongly dependent on the material parameters. Transient velocity overshoot has also been simulated, with the sudden application of fields up to 1600 kVm-1, appropriate to the gate-drain fields expected within an operational field effect transistor. The electron drift velocity relaxes to the saturation value of ~105 ms-1 within 4 ps, for all crystal structures. The steady state and transient velocity overshoot characteristics are in fair agreement with other recent calculations.

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