4-MOMENT HYDRODYNAMIC MODELING OF A SUBMICROMETER SEMICONDUCTOR-DEVICE IN A NON-PARABOLIC BAND-STRUCTURE

Two hydrodynamic models for a non-parabolic band structure are propose d in order to obtain closed sets of the first four moment equations de rived from the Boltzmann transport equation. Instead of using the Four ier-law heat flux to determine the energy flux and to close the first three moment equations as applied to the conventional hydrodynamic mod el, the energy flux is solved directly from the third-order moment equ ation. The physical quantities introduced in the third-order moment eq uation are expressed in terms of the lower-older moments and the avera ge parameters associated with the random velocity. To close the third- order moment equation, the average parameters related to the random ve locity are assumed to be energy dependent. Transport results for a sub micrometre silicon n(+)-n-n(+) diode obtained from the proposed four-m oment hydrodynamic models, compared with those from Monte Carlo simula tions and from three-moment hydrodynamic models, are studied in detail .