A STUDY OF THE NON-PARABOLIC HYDRODYNAMIC MODELING OF A SUBMICROMETERN(-N-N(+) DEVICE())

The common assumptions for closure of the first three moment equations with non-parabolic band structure have led to many inconsistencies as sociated with the electron temperature, effective mass and heat flux. The assumptions are involved in the heat flux based on the Fourier law and in the electron temperature determined from the average kinetic a nd drift energies. The inconsistencies resulting from these assumption s are studied and illustrated for electrons in silicon with a non-para bolic energy band. A simple alternative by means of which to avoid the inconsistent assumptions and to truncate the hierarchy of the hydrody namic equations with non-parabolic band structure is proposed. Instead of using the Fourier-law heat flux to close the hydrodynamic equation s, the energy flux is separated into fluxes carried by average and ran dom velocities. The proposed model and a Fourier-law-based hydrodynami c model, together with the Monte Carlo method, are applied to a silico n sub-micrometre n(+)-n-n(+) diode with a non-parabolic band at variou s applied voltages. Effects on electron transport in the sub-micrometr e device resulting from the assumptions of the Fourier-law heat flux a nd the electron temperature determined from the average kinetic and dr ift energies are investigated.