scholarly journals Assessing the quality of the excess chemical potential flux scheme for degenerate semiconductor device simulation

2021 ◽  
Vol 53 (3) ◽  
Author(s):  
Dilara Abdel ◽  
Patricio Farrell ◽  
Jürgen Fuhrmann
Keyword(s):  
Chemical Potential ◽  
Semiconductor Device ◽  
Semiconductor Devices ◽  
Degenerate Semiconductor ◽  
Excess Chemical Potential ◽  
Integral Flux ◽  
Flux Approximation ◽  
Continuous Current ◽  
Current Flows ◽  
Volume Method

AbstractThe van Roosbroeck system models current flows in (non-)degenerate semiconductor devices. Focusing on the stationary model, we compare the excess chemical potential discretization scheme, a flux approximation which is based on a modification of the drift term in the current densities, with another state-of-the-art Scharfetter–Gummel scheme, namely the diffusion-enhanced scheme. Physically, the diffusion-enhanced scheme can be interpreted as a flux approximation which modifies the thermal voltage. As a reference solution we consider an implicitly defined integral flux, using Blakemore statistics. The integral flux refers to the exact solution of a local two point boundary value problem for the continuous current density and can be interpreted as a generalized Scharfetter–Gummel scheme. All numerical discretization schemes can be used within a Voronoi finite volume method to simulate charge transport in (non-)degenerate semiconductor devices. The investigation includes the analysis of Taylor expansions, a derivation of error estimates and a visualization of errors in local flux approximations to extend previous discussions. Additionally, drift-diffusion simulations of a p–i–n device are performed.

Element Edge Based Discretization for TCAD Device Simulation

2021 ◽  
Author(s):  
Juan Sanchez ◽  
Qiusong Chen
Keyword(s):  
Computer Aided Design ◽  
Field Effect Transistor ◽  
Semiconductor Device ◽  
Device Simulation ◽  
Polarization Effects ◽  
Effect Transistor ◽  
Edge Based ◽  
Volume Method ◽  
Aided Design ◽  
Novel Devices

<div><div><div><p>Technology computer-aided design (TCAD) semiconductor device simulators solve partial differential equations (PDE) using the finite volume method (FVM), or related methods. While this approach has been in use over several decades, its methods continue to be extended, and are still applicable for investigating novel devices. In this paper, we present an element edge based (EEB) FVM discretization approach suitable for capturing vector-field effects. Drawing from a 2D approach in the literature, we have extended this method to 3D. We implemented this method in a TCAD semiconductor device simulator, which uses a generalized PDE (GPDE) approach to simulate de- vices with the FVM. We describe how our EEB method is compatible with the GPDE approach, allowing the modeling of vector effects using scripting. This method is applied to solve polarization effects in a 3D ferro capacitor, and a 2D ferroelectric field-effect transistor. An example for field- dependent mobility in a 3D MOSFET is also presented.</p></div></div></div>

scholarly journals Excess chemical potential of thiophene in [C4MIM] [BF4, Cl, Br, CH3COO] ionic liquids, determined by molecular simulations

RSC Advances ◽  
2021 ◽  
Vol 11 (47) ◽  
pp. 29394-29406
Author(s):  
Marco V. Velarde-Salcedo ◽  
Joel Sánchez-Badillo ◽  
Marco Gallo ◽  
Jorge López-Lemus
Keyword(s):  
Ionic Liquids ◽  
Chemical Potential ◽  
Molecular Simulations ◽  
Excess Chemical Potential

Excess chemical potential of thiophene in imidazolium-based ionic liquids [C4mim][BF4], [C4mim][Cl], [C4mim][Br], and [C4mim][CH3COO] determined by molecular simulations.

Higher Resolution Hybrid-Upwind Spectral Finite-Volume Methods, for Flow in Porous and Fractured Media on Unstructured Grids

2021 ◽  
Author(s):  
Yawei Xie ◽  
Michael G. Edwards
Keyword(s):  
Finite Volume Method ◽  
Finite Volume ◽  
Unstructured Grids ◽  
Concentration Field ◽  
Convective Transport ◽  
High Order ◽  
Spectral Volume ◽  
Flux Approximation ◽  
Triangular Cell ◽  
Volume Method

Abstract A novel higher resolution spectral volume method coupled with a control-volume distributed multi-Point flux approximation (CVD-MPFA) is presented on unstructured triangular grids for subsurface reservoir simulation. The flow equations involve an essentially hyperbolic convection equation coupled with an elliptic pressure equation resulting from Darcy’s law together with mass conservation. The spectral volume (SV) method is a locally conservative, efficient high-order finite volume method for convective flow. In 2D geometry, the triangular cell is subdivided into sub-cells, and the average state variables in the sub-cells are used to reconstruct a high-order polynomial in the triangular cell. The focus here is on an efficient strategy for reconstruction of both a higher resolution approximation of the convective transport flux and Darcy-flux approximation on sub-cell interfaces, which is also coupled with a discrete fracture model. The strategy involves coupling of the SV method and reconstructed CVD-MPFA fluxes at the faces of the spectral volume, to obtain an efficient finer scale higher resolution finite-volume method which solves for both the saturation and pressure. A limiting procedure based on a Barth-Jespersen type limiter is used to prevent non-physical oscillations on unstructured grids. The fine scale saturation/concentration field is then updated via the reconstructed finite volume approximation over the sub-cell control-volumes. Performance comparisons are presented for two phase flow problems on 2D unstructured meshes including fractures. The results demonstrate that the spectral-volume method achieves further enhanced resolution of flow and fronts in addition to that of achieved by the standard higher resolution method over first order upwind, while improving upon efficiency.

A Finite Volume Method for the Multi Subband Boltzmann Equation with Realistic 2D Scattering in Double Gate MOSFETs

2011 ◽  
Vol 10 (2) ◽  
pp. 305-338 ◽  
Author(s):  
Tiao Lu ◽  
Gang Du ◽  
Xiaoyan Liu ◽  
Pingwen Zhang
Keyword(s):  
Finite Volume Method ◽  
Finite Volume ◽  
Semiconductor Device ◽  
Field Effect Transistors ◽  
Mean Free Path ◽  
Transport Problem ◽  
Oxide Semiconductor ◽  
Double Gate ◽  
Boltzmann Transport ◽  
Volume Method

AbstractWe propose a deterministic solver for the time-dependent multi-subband Boltzmann transport equation (MSBTE) for the two dimensional (2D) electron gas in double gate metal oxide semiconductor field effect transistors (MOSFETs) with flared out source/drain contacts. A realistic model with six-valleys of the conduction band of silicon and both intra-valley and inter-valley phonon-electron scattering is solved. We propose a second order finite volume method based on the positive and flux conservative (PFC) method to discretize the Boltzmann transport equations (BTEs). The transport part of the BTEs is split into two problems. One is a 1D transport problem in the position space, and the other is a 2D transport problem in the wavevector space. In order to reduce the splitting error, the 2D transport problem in the wavevector space is solved directly by using the PFC method instead of splitting into two 1D problems. The solver is applied to a nanoscale double gate MOSFET and the current-voltage characteristic is investigated. Comparison of the numerical results with ballistic solutions show that the scattering influence is not ignorable even when the size of a nanoscale semiconductor device goes to the scale of the electron mean free path.

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