Hydrodynamic carrier transport in semiconductors with multiple band minima

Carrier transport equations for analysis of semiconductor devices fabricated in materials with multiple band minima, such as GaAs, are presented. An approach is taken in which the carrier density is conserved and an approximation to the distribution function in terms of quasi-Fermi potentials, carrier temperatures, and other fixed parameters is used that satisfies the particle energy and temperature distributions for each valley in the material. A model of a GaAs MESFET, which illustrates the importance of the physical effects and achieves reasonable agreement with experiment without use of adjustable parameters, is presented as an example