Atomistic approach to alloy scattering in Si1−xGex

Mehrotra, Saumitra Raj; Paul, Abhijeet; Klimeck, Gerhard

doi:10.1063/1.3583983

Cited by 26 publications

(16 citation statements)

References 13 publications

(11 reference statements)

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“…36 Generally, however, δV deviates from the conduction band differences, 156 and should be estimated from empirical tightbinding parameters. [169][170][171][172] Using Eqs. (113) and (114), the matrix element Eq.…”

Section: Alloy Scatteringmentioning

confidence: 99%

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Modeling techniques for quantum cascade lasers

Jirauschek

Kubis

2014

Applied Physics Reviews

218

178

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Quantum cascade lasers are unipolar semiconductor lasers covering a wide range of the infrared and terahertz spectrum. Lasing action is achieved by using optical intersubband transitions between quantized states in specifically designed multiple-quantum-well heterostructures. A systematic improvement of quantum cascade lasers with respect to operating temperature, efficiency and spectral range requires detailed modeling of the underlying physical processes in these structures. Moreover, the quantum cascade laser constitutes a versatile model device for the development and improvement of simulation techniques in nano- and optoelectronics. This review provides a comprehensive survey and discussion of the modeling techniques used for the simulation of quantum cascade lasers. The main focus is on the modeling of carrier transport in the nanostructured gain medium, while the simulation of the optical cavity is covered at a more basic level. Specifically, the transfer matrix and finite difference methods for solving the one-dimensional Schr\"odinger equation and Schr\"odinger-Poisson system are discussed, providing the quantized states in the multiple-quantum-well active region. The modeling of the optical cavity is covered with a focus on basic waveguide resonator structures. Furthermore, various carrier transport simulation methods are discussed, ranging from basic empirical approaches to advanced self-consistent techniques. The methods include empirical rate equation and related Maxwell-Bloch equation approaches, self-consistent rate equation and ensemble Monte Carlo methods, as well as quantum transport approaches, in particular the density matrix and non-equilibrium Green's function (NEGF) formalism. The derived scattering rates and self-energies are generally valid for n-type devices based on one-dimensional quantum confinement, such as quantum well structures

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Section: Alloy Scatteringmentioning

confidence: 99%

“…This figure shows the exact (solid) as well as the approximated [Eq. (169), dashed] result of (1 + 2N Q ) at 19 meV.…”

Section: Scattering From Longitudinal Acoustic Phononsmentioning

confidence: 99%

Modeling techniques for quantum cascade lasers

Jirauschek

Kubis

2014

Applied Physics Reviews

218

178

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“…[3]. We extend the atomistic approach to be applicable to general devices as well as bulk materials [6].…”

Section: Simulation Modelmentioning

confidence: 99%

Physical understanding of alloy scattering in SiGe channel for high-performance strained pFETs

Jeong

Park

Dhar

et al. 2013

2013 IEEE International Electron Devices Meeting

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For devices beyond the 14nm node, it is important to investigate performance boosters such as high mobility channels. Although pure Ge offers a higher hole mobility than Si, conventional problems like surface passivation and its integration with Si makes SiGe alloy with low Ge mole fraction a viable option. The significance of alloy scattering, however, has been widely debated [1-3], so the accurate modeling of alloy scattering in SiGe channel has become an important issue to predict the performance of future SiGebased FETs. Usually, the calculation of alloy scattering mobility assumes an alloy scattering center in a simple analytical form with some fitting parameters, which is a good practical approach but has a limited predictability. In this paper, an atomistic tight-binding simulation is used to study alloy scattering in SiGe-based FETs, and to compare with experimental data. We conclude (i) although it is essentially impossible to avoid alloy scattering in SiGe material, (ii) high-mobility is indeed achieved in SiGe channel by combining lattice-mismatch stresses from Si virtual substrate with stresses from Source/Drain(SD) stressor.

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“…Alloy scattering is an elastic scattering mechanism that happens when a moving carrier faces a varying potential landscape due different atomic species. An effective scattering potential Δ U is used to describe the strength of the alloy scattering rate 4. The momentum relaxation rate due to alloy disorder in Si 1– x Ge x can be written as in Eq.…”

Section: Simulation Approachmentioning

confidence: 99%

“…Si 1– x Ge x is expected to suffer from added alloy disorder besides the scattering due to phonons at room temperature. The role of alloy and phonon scattering in bulk and thin body Si 1– x Ge x structures has been discussed extensively in literature, however, little theoretical work has been done in regard to nanowires 3–5. In this work, phonon and alloy mobility calculations are performed for 5 nm diameter intrinsic SiGe nanowires at low carrier concentration of p = 5 × 10 18 cm –3 .…”

Section: Introductionmentioning

confidence: 99%

Atomistic simulation of phonon and alloy limited hole mobility in Si_1–xGe_x nanowires

Mehrotra

Long

Povolotskyi

et al. 2013

Physica Rapid Research Ltrs

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The role of alloy and phonon scattering is theoretically explored in 5 nm diameter SiGe nanowires at room temperature. Low‐field mobility calculations are performed by utilizing sp3d5ds*‐spin–orbit‐coupled tight binding model for electronic structure and Boltzmann transport formalism. Three different transport orientations 〈100〉, 〈110〉 and 〈111〉 are considered. Alloy scattering is found to play an important role in these Si1–xGex nanowires, leading to a characteristic ‘U’ shaped mobility curve as a function of alloy composition. It is concluded that to extract any advantage of higher Ge hole mobility by alloying, Ge% > 70% is needed. Furthermore, the 〈111〉 channel orientation exhibits the highest hole mobility while 〈100〉 has the lowest hole mobility for any given alloy composition. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Atomistic approach to alloy scattering in Si1−xGex

Cited by 26 publications

References 13 publications

Modeling techniques for quantum cascade lasers

Modeling techniques for quantum cascade lasers

Physical understanding of alloy scattering in SiGe channel for high-performance strained pFETs

Atomistic simulation of phonon and alloy limited hole mobility in Si_1–xGe_x nanowires

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Atomistic approach to alloy scattering in Si1−xGex

Cited by 26 publications

References 13 publications

Modeling techniques for quantum cascade lasers

Modeling techniques for quantum cascade lasers

Physical understanding of alloy scattering in SiGe channel for high-performance strained pFETs

Atomistic simulation of phonon and alloy limited hole mobility in Si1–xGex nanowires

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Product

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Atomistic simulation of phonon and alloy limited hole mobility in Si_1–xGe_x nanowires