scholarly journals The Chapman-Enskog Expansion and the Quantum Hydrodynamic Model for Semiconductor Devices

VLSI Design ◽  
2000 ◽  
Vol 10 (4) ◽  
pp. 415-435 ◽  
Author(s):  
Carl L. Gardner ◽  
Christian Ringhofer

A “smooth” quantum hydrodynamic (QHD) model for semiconductor devices is derived by a Chapman-Enskog expansion of the Wigner-Boltzmann equation which can handle in a mathematically rigorous way the discontinuities in the classical potential energy which occur at heterojunction barriers in quantum semiconductor devices. A dispersive quantum contribution to the heat flux term in the QHD model is introduced.

VLSI Design ◽  
1999 ◽  
Vol 9 (4) ◽  
pp. 351-355
Author(s):  
Carl L. Gardner

The “smooth” quantum hydrodynamic (QHD) model is derived specifically to handle in a mathematically rigorous way the discontinuities in the classical potential energy which occur at heterojunction barriers in quantum semiconductor devices. Smooth QHD model simulations of the resonant tunneling diode are presented which exhibit enhanced negative differential resistance when compared with simulations using the original O(ħ2) QHD model. In addition, smooth QHD simulations of a classical electron shock wave are presented which agree with classical hydrodynamic model simulations and which do not exhibit the spurious dispersive oscillations of the O(ħ2) QHD model.


2007 ◽  
Vol 17 (02) ◽  
pp. 253-275 ◽  
Author(s):  
BO LIANG ◽  
KAIJUN ZHANG

In this paper we study the steady-state quantum hydrodynamic model for semiconductors. The existence of solutions on the bipolar QHD model is obtained in the case of sufficiently small relaxation time. Uniqueness results are showed both in the thermal equilibrium states and the scaled Planck constant being large enough. The relaxation time and dispersive limit are performed on the bipolar and unipolar equations, respectively. In a sense, we have made a complete answer to the original unsolved problems of the steady-state QHD model.


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