Investigation of moments-based transport models applied to plasma waves and the Dyakonov–Shur instability

Linn, Tobias; Kargar, Zeinab; Jungemann, C.

doi:10.1088/1361-6641/aaf27a

Cited by 6 publications

(4 citation statements)

References 26 publications

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“…The complex 1D model based on four BTE moments is proposed in Ref. [35]. A small signal case was considered in the paper for comparison with a deterministic BTE solution.…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional hydrodynamic modelling of AlGaN/GaN transistor-based THz detectors

Vyšniauskas,

Ikamas,

Vizbaras

et al. 2023

physics

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Here, we report on numerical modelling of AlGaN/GaN HEMT terahertz detectors using a two-dimensional solver based on three Boltzmann transport equation (BTE) moments and the Poisson equation. We use the Synopsys TCAD Sentaurus program package, which offers a wide material database and the possibility to include traps and polarization charges for the formation of the channel without any doping. The implications of different levels of model simplifications are addressed both analytically and numerically. We calculated the current responsivity R, to THz radiation on the drain voltage in the frequency range 0.01-3.0 THz for three AlGaN layer thicknesses d= 15, 20 and 25 nm and different gate lengths. We demonstrate that only a hydrodynamic model can reproduce the change in the sign in current responsivity at the gate voltage UG9 (R1 = 0 at UG = UG0). The energy flux factor in the energy balance equation determines this effect. For the simulated structures, we find that the noise equivalent power may be as low as 0.1 pW/VHz at 0.04 THz and 10 pW/VHz at 3.0 THz.

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“…The complex 1D model based on four BTE moments is proposed in Ref. [35]. A small signal case was considered in the paper for comparison with a deterministic BTE solution.…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional hydrodynamic modelling of AlGaN/GaN transistor-based THz detectors

Vyšniauskas,

Ikamas,

Vizbaras

et al. 2023

physics

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“…Although the methods developed previously for planar transistors could be applied to nanowire transistors, it is not clear whether the assumptions on which these models are based hold in the case of quasi-ballistic transport, which is a prerequisite for plasma instabilities [14]. Therefore, we discuss in addition to the drift-diffusion (DD) model, which is similar to the transport model used by Dyakonov and Shur, also the Boltzmann transport equation (BE) from which the DD model can be derived under rather stringent approximations [15].…”

Section: Introductionmentioning

confidence: 99%

A numerical approach to quasi-ballistic transport and plasma oscillations in junctionless nanowire transistors

2020

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A numerical framework for DC and RF small-signal simulations of nanowire transistors is presented, which is based on the self-consistent solution of the Poisson, Schrödinger, and Boltzmann transport equations and is stable for the entire range from weak to strong particle scattering. The proposed approach does not suffer from the deficiencies due to the transformation of the Boltzmann transport equation into the energy space and can handle the quasi-ballistic case. This is a key requirement for the investigation of plasma resonances and other high-mobility phenomena. The in-house solver is validated with results of a previously developed simulator based on the H-transformation for a conventional N + NN + silicon transistor with strong scattering. Then, its results are compared with those of moments-based models and it is shown that these do not provide a satisfactory description of the electron dynamics in the quasi-ballistic transport regime. Furthermore, the internal boundary conditions of the transport models at the contacts are found to have a significant impact on plasma resonances and the physics-based thermal-bath boundary condition strongly suppresses them.

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“…Furthermore, two moments are not enough since heating effects of the electron gas can not be described. The closure relation is also too simplistic and inconsistent with a non-zero current density [20].…”

Section: Introductionmentioning

confidence: 99%

Simulation of THz Oscillations in Semiconductor Devices Based on Balance Equations

et al. 2020

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Instabilities of electron plasma waves in high-mobility semiconductor devices have recently attracted a lot of attention as a possible candidate for closing the THz gap. Conventional moments-based transport models usually neglect time derivatives in the constitutive equations for vectorial quantities, resulting in parabolic systems of partial differential equations (PDE). To describe plasma waves however, such time derivatives need to be included, resulting in hyperbolic rather than parabolic systems of PDEs; thus the fundamental nature of these equation systems is changed completely. Additional nonlinear terms render the existing numerical stabilization methods for semiconductor simulation practically useless. On the other hand there are plenty of numerical methods for hyperbolic systems of PDEs in the form of conservation laws. Standard numerical schemes for conservation laws, however, are often either incapable of correctly handling the large source terms present in semiconductor devices due to built-in electric fields, or rely heavily on variable transformations which are specific to the equation system at hand (e.g. the shallow water equations), and can not be generalized easily to different equations. In this paper we develop a novel well-balanced numerical scheme for hyperbolic systems of PDEs with source terms and apply it to a simple yet non-linear electron transport model.

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Investigation of moments-based transport models applied to plasma waves and the Dyakonov–Shur instability

Cited by 6 publications

References 26 publications

Two-dimensional hydrodynamic modelling of AlGaN/GaN transistor-based THz detectors

Two-dimensional hydrodynamic modelling of AlGaN/GaN transistor-based THz detectors

A numerical approach to quasi-ballistic transport and plasma oscillations in junctionless nanowire transistors

Simulation of THz Oscillations in Semiconductor Devices Based on Balance Equations

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