STUDY OF HIGH-FIELD ELECTRON-TRANSPORT IN SEMICONDUCTORS USING BALANCE-EQUATIONS FOR NONPARABOLIC MULTIVALLEY SYSTEMS

Balance equations for high-field electron transport in nonparabolic mu ltiband (multivalley) semiconductors are proposed based on the Heisenb erg equations of motion for the total physical momentum, the total ene rgy and the population of carriers in each energy band (each valley), and the statistical average with respect to an initial density matrix having a lattice wave-vector shift, an electron temperature, and a che mical potential for each energy band (each valley) as parameters. As a n example, these equations are applied to the discussion of hot-electr on transport in bulk Si, assuming Kane-type energy dispersion for six elliptical valleys. The theoretical results are in good agreement with experiments and with Monte Carlo simulations, over the entire range o f the electric field up to 140 kV/cm. (C) 1996 American Institute of P hysics.