E.D. LYUMKIS, B.S. POLSKY, A.I. SHUR and P. VISOCKY
An efficient numerical method for the solution of hot‐carrier transport equations describing transient processes in submicrometer semiconductor devices is proposed. The…
Abstract
An efficient numerical method for the solution of hot‐carrier transport equations describing transient processes in submicrometer semiconductor devices is proposed. The calculations of transient processes in submicrometer MOS transistor were carried out and compared with the results obtained by conventional drift‐diffusion model.
R. VANKEMMEL, W. SCHOENMAKER and K. DE MEYER
This paper presents a new discretization technique of the hydrodynamic energy balance model based on a finite‐element formulation. The concept of heat source lumping is…
Abstract
This paper presents a new discretization technique of the hydrodynamic energy balance model based on a finite‐element formulation. The concept of heat source lumping is introduced, and the thermal conductivity model includes the effect of varying both carrier concentrations and temperatures. The energy balance equation is formulated to account for kinetic energy as a convective flow. The new discretization method has the advantage that it allows for assembling the functions out of elementary variables available over elements instead of along element links. Therefore, theoretically, calculation of the Jacobian should be three times faster than by the classic method. Results are given for three examples. The method suffers from mathematical instabilities, but provides a good basis for future work to solve these problems.
Giovanni Mascali and Vittorio Romano
This paper intends to present a hydrodynamical model which describes the hole motion in silicon and couples holes and electrons.
Abstract
Purpose
This paper intends to present a hydrodynamical model which describes the hole motion in silicon and couples holes and electrons.
Design/methodology/approach
The model is based on the moment method and the closure of the system of moment equations is obtained by using the maximum entropy principle (hereafter MEP). The heavy, light and split‐off valence bands are considered. The first two are described by taking into account their warped shape, while for the split‐off band a parabolic approximation is used.
Findings
The model for holes is coupled with an analogous one for electrons, so obtaining a complete description of charge transport in silicon. Numerical simulations are performed both for bulk silicon and a p‐n junction.
Research limitations/implications
The model uses a linear approximation of the maximum entropy distribution in order to close the system of moment equations. Furthermore, the non‐parabolicity of the heavy and light bands is neglected. This implies an approximation on the high field results. This issue is under current investigation.
Practical implications
The paper improves the previous hydrodynamical models on holes and furnishes a complete model which couples electrons and holes. It can be useful in simulations of bipolar devices.
Originality/value
The results of the paper are new since a better approximation of the band structure is used and a description of both electron and hole behavior is present, therefore the results are of a certain relevance for the theory of charge transport in semiconductors.
Details
Keywords
A.M. Blokhin and R.S. Bushmanov
The purpose of this paper is to reply to the following question: do there exist piecewise smooth solutions to the 2D MEP hydrodynamical model of charge transport in semiconductors…
Abstract
Purpose
The purpose of this paper is to reply to the following question: do there exist piecewise smooth solutions to the 2D MEP hydrodynamical model of charge transport in semiconductors with smooth parts separated by a surface of strong discontinuity?
Design/methodology/approach
A standard approach is used to obtain jump conditions for the balance equations under consideration.
Findings
For the balance equations of charge transport in semiconductors based on the maximum entropy principle Rankine‐Hugoniot jump conditions were derived and studied. Considering the important case of planar discontinuity, the authors discuss the legitimacy of the introduction of surface charge and surface current in the Rankine‐Hugoniot jump conditions.
Research limitations/implications
The jump conditions are derived for the balance equations written for the case of the parabolic approximation of energy bands. However, it is possible also to perform the analysis of corresponding jump conditions for the case of Kane dispersion relation approximation.
Originality/value
The paper presents derivation and study of Rankine‐Hugoniot jump conditions for the 2D MEP hydrodynamical model of charge transport in semiconductors.
Details
Keywords
Giovanni Mascali and Vittorio Romano
On the basis of the maximum entropy principle, seeks to formulate a hydrodynamical model for electron transport in GaAs semiconductors, which is free of any fitting parameter.
Abstract
Purpose
On the basis of the maximum entropy principle, seeks to formulate a hydrodynamical model for electron transport in GaAs semiconductors, which is free of any fitting parameter.
Design/methodology/approach
The model considers the conduction band to be described by the Kane dispersion relation and includes both Γ and L valleys. Takes into account electron‐non‐polar optical phonon, electron‐polar optical phonon and electro‐acoustic phonon scattering.
Findings
The set of balance equation of the model forms a quasilinear hyperbolic system and for its numerical integration a recent high‐order shock‐capturing central differencing scheme has been employed.
Originality/value
Presents the results of simulations of n+ ‐n‐n+ GaAs diode and Gunn oscillator.