BALANCE-EQUATION APPROACH TO NONUNIFORM ELECTRON-TRANSPORT IN NONPARABOLIC SEMICONDUCTORS

On the basis of the Lei-Ting balance-equation transport theory recentl y developed for nonparabolic energy band, rr-e propose a hydrodynamic approach to the spatially inhomogeneous electron transport in semicond uctor devices. In the present approach, the momentum and energy collis ion terms are expressed by two nonlinear functions, the frictional acc eleration and energy-loss rate, which give a detailed scattering-proce ss-level description of nonstationary and nonlocal charge transport in the system. This approach allows one to calculate self-consistently t he transport parameters within the model itself based on the primary m aterial data (hand structure, deformation potential constant, etc.), t hus it minimizes the uncertainty associated with the use of some empir ical relations for transport coefficients. As a demonstration of the a pproach, rr-e have carried out a numerical calculation for a submicrom eter Si n(+)nn(+) diode by assuming an isotropic Kane-type energy band . The results for electron velocity and energy, obtained at much less computing cost than the Monte-Carlo (MC) method, ale in good agreement with MC prediction. The influence of heat-flow term on electron trans port behaviour, especially on velocity overshoot, is also investigated .