Surface roughness limited mobility in multi-gate FETs with arbitrary cross-section

Badami, Oves; Lizzit, Daniel; Specogna, Ruben; Esseni, D.

doi:10.1109/iedm.2016.7838551

Cited by 5 publications

(13 citation statements)

References 13 publications

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“…Both k•p and empirical pseudopotential methods have been used to validate the effective masses and non-parabolic coefficients used in this work [23]. Throughout the work we have accounted for the wavefunction penetration into the oxide, which is also necessary for our formulation of surface roughness scattering [24], [25]. The wavefunction continuity at the oxide-semicoductor interface (continuity of ξ n (y, z) and W yz ∇ξ n (y, z)) is naturally satisfied in the Discrete Geometric Approach (DGA) [26].…”

Section: A Schrödinger-poisson-bte Solvermentioning

confidence: 99%

“…In the Boltzmann Transport equation all the relevant scattering mechanisms are included without resorting to any simplification like relaxation time approximation. The surface roughness scattering has been modeled with the recently developed nonlinear model, which allows us to use realistic values of the surface roughness parameters [24], [25].…”

Section: A Schrödinger-poisson-bte Solvermentioning

confidence: 99%

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Benchmarking of 3-D MOSFET Architectures: Focus on the Impact of Surface Roughness and Self-Heating

Badami

Lizzit

Driussi

et al. 2018

IEEE Trans. Electron Devices

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Tremendous improvements in the fabrication technology has allowed us to scale the physical dimensions of the transistors and also to develop different promising 3D architectures that may allow us to continue the Moore's law. In this work we perform a comparative delay analysis of different architectures and study the impact of surface roughness and self-heating on oncurrent using a comprehensive in-house simulation framework comprising of Schrödinger, Poisson and Boltzmann transport equations solvers along with relevant scattering mechanisms and self-heating. Our results highlight that the parasitic capacitance can alter the relative ranking of the architectures from delay point of view. We demonstrate that the surface roughness can cause architecture and material dependent degradation and hence it is necessary to account for it in simulations benchmarking different architectures.

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Section: A Schrödinger-poisson-bte Solvermentioning

confidence: 99%

Section: A Schrödinger-poisson-bte Solvermentioning

confidence: 99%

Benchmarking of 3-D MOSFET Architectures: Focus on the Impact of Surface Roughness and Self-Heating

Badami

Lizzit

Driussi

et al. 2018

IEEE Trans. Electron Devices

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“…In this approach, quantization normal to the transport direction is handled by solving the Schrödinger equation in each device slice and then solving the Boltzmann Transport Equation (BTE) along the channel direction using the derivative of the subband energy as the driving force [16,17]. The problem can be tackled either with the Monte Carlo method [18,19] or with deterministic approaches [20,21]. In the former case, we obtain what is known as Multi-valley/Multi-subband Monte Carlo (MV-MSMC) [17].…”

Section: Introductionmentioning

confidence: 99%

Modeling Nanoscale III–V Channel MOSFETs with the Self-Consistent Multi-Valley/Multi-Subband Monte Carlo Approach

et al. 2021

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We describe the multi-valley/multi-subband Monte Carlo (MV–MSMC) approach to model nanoscale MOSFETs featuring III–V semiconductors as channel material. This approach describes carrier quantization normal to the channel direction, solving the Schrödinger equation while off-equilibrium transport is captured by the multi-valley/multi-subband Boltzmann transport equation. In this paper, we outline a methodology to include quantum effects along the transport direction (namely, source-to-drain tunneling) and provide model verification by comparison with Non-Equilibrium Green’s Function results for nanoscale MOSFETs with InAs and InGaAs channels. It is then shown how to use the MV–MSMC to calibrate a Technology Computer Aided Design (TCAD) simulation deck based on the drift–diffusion model that allows much faster simulations and opens the doors to variability studies in III–V channel MOSFETs.

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“…This fact leads to the excessively large roughness assumed to represent the experimental mobility. On the other hand, a nonlinear model of surface roughness scattering has been recently proposed [20]- [23], which can include the higher order perturbations. This model has explained the experimental results with reasonable roughness parameters.…”

mentioning

confidence: 99%

“…This model has explained the experimental results with reasonable roughness parameters. These previous studies [20]- [23] are valuable as the first introduction of the nonlinear model. However, their formulations are still insufficient because the nonlinear perturbation effect on wavefunctions of confined electrons, which does not occur for the linear perturbation, is neglected.…”

mentioning

confidence: 99%

Formulation of Ground States for 2DEG at Rough Surfaces and Application to Nonlinear Model of Surface Roughness Scattering in nMOSFETs

Sumita

Kang

Toprasertpong

et al. 2023

IEEE J. Electron Devices Soc.

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Electron mobility in extremely-thin-body (ETB) nanosheet channels and at cryogenic temperature is known to be dominated by surface roughness scattering. However, the conventional model of surface roughness scattering lacks accuracy because it requires the use of excessive roughness parameters to represent the experimental results. One of the main difficulties for the surface roughness scattering model is that the higher-order perturbations should be accurately included in the model because the surface roughness scattering is a strongly nonlinear phenomenon. Therefore, in this study, the formulation of ground states of two-dimensional electron gas (2DEG) at rough surfaces is derived by introducing a concept of the space-averaged perturbation Hamiltonian. This revised formulation of 2DEG at rough surfaces is different from the conventional solution for 2DEG at the flat surface. The space-averaged perturbation Hamiltonian is invisible in the linearized perturbation system, while its effect is significant in the system with the nonlinear perturbation energy. We combine the revised 2DEG formulation with a nonlinear model of surface roughness scattering and calculate the 2DEG mobility of the bulk Si and ETB Si-oninsulator (SOI) nMOSFETs. As a result, the experimental mobility of bulk and ETB SOI nMOSFETs is well explained in a wide temperature range of 4.2 to 300 K by using the roughness parameters experimentally obtained by transmission electron microscopy (TEM), which also supports the understanding of mobility at cryogenic temperature. The revised nonlinear model reveals that surface roughness scattering under the present model is 13 times stronger than that predicted by the conventional linear model.

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Surface roughness limited mobility in multi-gate FETs with arbitrary cross-section

Cited by 5 publications

References 13 publications

Benchmarking of 3-D MOSFET Architectures: Focus on the Impact of Surface Roughness and Self-Heating

Benchmarking of 3-D MOSFET Architectures: Focus on the Impact of Surface Roughness and Self-Heating

Modeling Nanoscale III–V Channel MOSFETs with the Self-Consistent Multi-Valley/Multi-Subband Monte Carlo Approach

Formulation of Ground States for 2DEG at Rough Surfaces and Application to Nonlinear Model of Surface Roughness Scattering in nMOSFETs

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