MONTE CARLO SIMULATIONS OF STEADY-STATE TRANSPORT IN WURTZITE PHASE GaN SUBMICROMETER n+nn+ DIODE

Monte Carlo simulation of electron transport in a GaN diode of n+nn+ structure with a 0.4 or 0.6 μm long active layer is described. The anode voltage ranges from 10 to 50 V. The distributions of electron energies and electron velocities, and the profiles of the electron density, electric field, potential and average electron velocity are computed. Based on these data, the near ballistic nature of the electron transport in the 0.4 μm-long diode and the importance of the back-scattering of electrons from the anode n+-layer are discussed. Also, the effects of the lattice temperature and doping on the length of the active layer are discussed.

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MONTE CARLO SIMULATION OF STEADY-STATE TRANSPORT IN SUBMICROMETER InP AND GaAsn+–i(n)–n+ DIODE

Modern Physics Letters B ◽

10.1142/s0217984910022603 ◽

2010 ◽

Vol 24 (06) ◽

pp. 549-560 ◽

Cited By ~ 2

Author(s):

H. ARABSHAHI ◽

M. REZAEE ROKN-ABADI ◽

F. BADIEIAN BAGHSIAHI ◽

M. R. KHALVATI

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Steady State ◽

Electron Transport ◽

Anode Voltage ◽

Electronic States ◽

Electron Velocity ◽

Back Scattering ◽

Simulation Results ◽

Average Electron

Monte Carlo simulation of electron transport in an InP diode of n+–i(n)–n+ structure is compared with GaAs diode. The anode voltage ranges from 0.5 to 1.5 V. The distributions of electron energies and electron velocities and the profiles of the electron density, electric field and potential and average electron velocity are computed. Based on these data, the near ballistic nature of the electron transport in the 0.2 μm-long diode and the importance of the back-scattering of electrons from the anode n+-layer are discussed. In addition, the effects of the lattice temperature and doping on the length of the active layer are discussed. Electronic states within the conduction band valleys at the Γ, L, and X are represented by non-parabolic ellipsoidal valleys centered on important symmetry points of the Brillouin zone. Our simulation results have also shown that the electron velocity characteristics in InP diode are more sensitive to temperature than in other III–V semiconductors such as GaAs .

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Monte Carlo simulation of electron transport in the III-nitride wurtzite phase materials system: binaries and ternaries

IEEE Transactions on Electron Devices ◽

10.1109/16.906448 ◽

2001 ◽

Vol 48 (3) ◽

pp. 535-542 ◽

Cited By ~ 256

Author(s):

M. Farahmand ◽

C. Garetto ◽

E. Bellotti ◽

K.F. Brennan ◽

M. Goano ◽

...

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Electron Transport ◽

Wurtzite Phase

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TEMPERATURE DEPENDENCE OF HIGH FIELD ELECTRON TRANSPORT PROPERTIES IN WURTZITE PHASE GaN FOR DEVICE MODELING

International Journal of Modern Physics B ◽

10.1142/s0217979208048620 ◽

2008 ◽

Vol 22 (22) ◽

pp. 3915-3922 ◽

Cited By ~ 1

Author(s):

A. R. BINESH ◽

H. ARABSHAHI ◽

G. R. EBRAHIMI ◽

M. REZAEE ROKN-ABADI

Keyword(s):

Electron Transport ◽

Electric Fields ◽

Dominant Role ◽

Electron Velocity ◽

Differential Conductance ◽

Device Modeling ◽

Wurtzite Phase ◽

Ensemble Monte Carlo ◽

Electron Transport Properties ◽

High Electric Fields

An ensemble Monte Carlo simulation has been used to model bulk electron transport at room and higher temperatures as a function of high electric fields. Electronic states within the conduction band valleys at the Γ1, U, M, Γ3 and K are represented by non-parabolic ellipsoidal valleys centred on important symmetry points of the Brillouin zone. The simulation shows that intervalley electron transfer plays a dominant role in GaN in high electric fields leading to a strongly inverted electron distribution and to a large negative differential conductance. Our simulation results have also shown that the electron velocity in GaN is less sensitive to temperature than in other III-V semiconductors like GaAs . So GaN devices are expected to be more tolerant to self-heating and high ambient temperature device modeling. Our steady state velocity-field characteristics are in fair agreement with other recent calculations.

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Full Band Monte Carlo Comparison of Wurtzite and Zincblende Phase GaN MESFETs

MRS Proceedings ◽

10.1557/proc-595-f99w11.13 ◽

1999 ◽

Vol 595 ◽

Author(s):

Maziar Farahmand ◽

Kevin F. Brennan

Keyword(s):

Monte Carlo ◽

Breakdown Voltage ◽

Cutoff Frequency ◽

Electron Velocity ◽

Wurtzite Phase ◽

Velocity Overshoot ◽

Density Of Electronic States ◽

Full Band ◽

Self Consistent ◽

Output Characteristics

AbstractThe output characteristics, cutoff frequency, breakdown voltage and the transconductance of wurtzite and zincblende phase GaN MESFETs have been calculated using a self-consistent, full band Monte Carlo simulation. It is found that the calculated breakdown voltage for the wurtzite device is considerably higher than that calculated for a comparable GaN zincblende phase device. The zincblende device is calculated to have a higher transconductance and cutoff frequency than the wurtzite device. The higher breakdown voltage of the wurtzite phase device is attributed to the higher density of electronic states for this phase compared to the zincblende phase. The higher cutoff frequency and transconductance of the zincblende phase GaN device is attributed to more appreciable electron velocity overshoot for this phase compared to that for the wurtzite phase. The maximum cutoff frequency and transconductance of a 0.1 μm gate-length zincblende GaN MESFET are calculated to be 220GHz and 210 mS/mm, respectively. The corresponding quantities for the wurtzite GaN device are calculated to be 160GHz and 158 mS/mm.

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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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INFLUENCE OF POLARIZATION CHARGES AND ELECTRON TRAPPING IN THE BUFFER LAYER IN WURTZITE PHASE AlGaN/GaN HFETs

Modern Physics Letters B ◽

10.1142/s0217984906011608 ◽

2006 ◽

Vol 20 (22) ◽

pp. 1397-1404 ◽

Cited By ~ 2

Author(s):

H. ARABSHAHI ◽

M. H. GHASEMIAN

Keyword(s):

Monte Carlo ◽

Electron Transport ◽

Buffer Layer ◽

Interface Layer ◽

Electron Trapping ◽

Wurtzite Phase ◽

Polarization Effects ◽

Ensemble Monte Carlo ◽

Current Collapse ◽

Gan Hfet

Ensemble Monte Carlo simulations have been performed to model electron transport in wurtzite phase AlGaN/GaN heterojunction FETs. Planar Al 0.2 Ga 0.8 N/GaN HFET structures with a 78 nm Al 0.2 Ga 0.8 N pseudomorphically strained layer were simulated, where the spontaneous and piezoelectric polarization effects were taken into account. Trap centers located in the buffer layer has also been simulated to include the effect of trapping levels on current collapse in GaN HFETs. The polarization effects was shown to not only increase the current density, but also improve the electron transport in the interface layer by inducing a higher electron density to the positive polarized sheet and away from the buffer layer.

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Monte Carlo Calculation Of High- And Low-Field AlxGa1−xN Electron Transport Characteristics

MRS Proceedings ◽

10.1557/proc-482-815 ◽

1997 ◽

Vol 482 ◽

Cited By ~ 12

Author(s):

J.D. Albrecht ◽

R. Wang ◽

P.P. Ruden ◽

M. Farahmand ◽

E. Bellotti ◽

...

Keyword(s):

Monte Carlo ◽

Electron Transport ◽

Electric Fields ◽

Phonon Scattering ◽

Linear Interpolation ◽

Potential Scattering ◽

Band Model ◽

Polar Optical Phonon ◽

Wurtzite Phase ◽

Low Field

AbstractThe Monte Carlo technique is used to simulate electron transport in bulk, wurtzite phase AlxGa1−xN. A multi-valley analytical band model consisting of five spherical, non-parabolic conduction band valleys at the Γ, U, M, and K symmetry points of the Brillouin zone is matched to band structures of GaN and AlN. Parameters for the AlxGa1−xN alloy are obtained by linear interpolation. The Monte Carlo simulations are performed for ambient temperatures in the range of 300K to 600K. Scattering mechanisms taken into account include ionized impurity scattering and alloy scattering, in addition to deformation potential scattering (intra- and inter-valley), and polar optical phonon scattering. We present results for the electron steady-state drift velocity and the valley occupancy for electric fields up to 500 kV/cm. Low-field drift mobilities are extracted from the Monte Carlo calculations as functions of the electron concentration, of the ambient temperature, and of the alloy composition.

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Full Band Monte Carlo Comparison of Wurtzite and Zincblende Phase GaN MESFETs

MRS Internet Journal of Nitride Semiconductor Research ◽

10.1557/s1092578300004865 ◽

2000 ◽

Vol 5 (S1) ◽

pp. 633-639

Author(s):

Maziar Farahmand ◽

Kevin F. Brennan

Keyword(s):

Monte Carlo ◽

Breakdown Voltage ◽

Cutoff Frequency ◽

Electron Velocity ◽

Wurtzite Phase ◽

Velocity Overshoot ◽

Density Of Electronic States ◽

Full Band ◽

Self Consistent ◽

Output Characteristics

The output characteristics, cutoff frequency, breakdown voltage and the transconductance of wurtzite and zincblende phase GaN MESFETs have been calculated using a self-consistent, full band Monte Carlo simulation. It is found that the calculated breakdown voltage for the wurtzite device is considerably higher than that calculated for a comparable GaN zincblende phase device. The zincblende device is calculated to have a higher transconductance and cutoff frequency than the wurtzite device. The higher breakdown voltage of the wurtzite phase device is attributed to the higher density of electronic states for this phase compared to the zincblende phase. The higher cutoff frequency and transconductance of the zincblende phase GaN device is attributed to more appreciable electron velocity overshoot for this phase compared to that for the wurtzite phase. The maximum cutoff frequency and transconductance of a 0.1 μm gate-length zincblende GaN MESFET are calculated to be 220GHz and 210 mS/mm, respectively. The corresponding quantities for the wurtzite GaN device are calculated to be 160GHz and 158 mS/mm.

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Integral Equations for Problems on Wave Propagation in Near-Earth Plasma

Symmetry ◽

10.3390/sym13081395 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1395

Author(s):

Danila Kostarev ◽

Dmitri Klimushkin ◽

Pavel Mager

Keyword(s):

Magnetic Field ◽

Integral Equations ◽

Field Potential ◽

Low Frequency ◽

Fredholm Equation ◽

Compression Waves ◽

Parallel Component ◽

Electric Field Potential ◽

The Magnetic Field ◽

Low Frequency Waves

We consider the solutions of two integrodifferential equations in this work. These equations describe the ultra-low frequency waves in the dipol-like model of the magnetosphere in the gyrokinetic framework. The first one is reduced to the homogeneous, second kind Fredholm equation. This equation describes the structure of the parallel component of the magnetic field of drift-compression waves along the Earth’s magnetic field. The second equation is reduced to the inhomogeneous, second kind Fredholm equation. This equation describes the field-aligned structure of the parallel electric field potential of Alfvén waves. Both integral equations are solved numerically.

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