TRANSPORT EFFECTS AND CHARACTERISTIC MODES IN THE MODELING AND SIMULATION OF SUBMICRON DEVICES

This paper has two major goals: 1) to study the effect of the common p ractice of neglecting the convective terms (inertial approximation) in the hydrodynamic model in the simulation of n(+)-n-n(+) diodes and tw o dimensional MESFET devices; and 2) to test analytical criteria, form ulated in terms of characteristic values of the Jacobian matrix, as a method of determining the impact of first derivative perturbation term s in this model, and in related energy transport models. This characte ristic value analysis can be thought of as generalizing the usual anal ytical solution of first order linear systems of ordinary differential equations with constant coefficients, Concerning 1), we find that the inertial approximation is invalid near the diode junctions, and near the contact regions of the MESFET device, In regard to 2), we find a p roper arrangement of terms, expressing the flux, such that the first d erivative part of the system is hyperbolic, both for the hydrodynamic model and the energy transport model, For the hydrodynamic model, two forms of the heat conduction term are studied, including the case of a convective term, This suggests and validates the use of shock capturi ng algorithms for the simulation.