@Article{JCM-41-909,
author = {Mu , Pengcong and Zheng , Weiying},
title = {A Positivity-Preserving Finite Element Method for Quantum Drift-Diffusion Model},
journal = {Journal of Computational Mathematics},
year = {2023},
volume = {41},
number = {5},
pages = {909--932},
abstract = {<p style="text-align: justify;">In this paper, we propose a positivity-preserving finite element method for solving the
three-dimensional quantum drift-diffusion model. The model consists of five nonlinear
elliptic equations, and two of them describe quantum corrections for quasi-Fermi levels.
We propose an interpolated-exponential finite element (IEFE) method for solving the two
quantum-correction equations. The IEFE method always yields positive carrier densities
and preserves the positivity of second-order differential operators in the Newton linearization of quantum-correction equations. Moreover, we solve the two continuity equations
with the edge-averaged finite element (EAFE) method to reduce numerical oscillations of
quasi-Fermi levels. The Poisson equation of electrical potential is solved with standard
Lagrangian finite elements. We prove the existence of solution to the nonlinear discrete
problem by using a fixed-point iteration and solving the minimum problem of a new discrete functional. A Newton method is proposed to solve the nonlinear discrete problem.
Numerical experiments for a three-dimensional nano-scale FinFET device show that the
Newton method is robust for source-to-gate bias voltages up to 9V and source-to-drain
bias voltages up to 10V.</p>},
issn = {1991-7139},
doi = {https://doi.org/10.4208/jcm.2206-m2021-0353},
url = {http://global-sci.org/intro/article_detail/jcm/21679.html}
}