2-DIMENSIONAL NUMERICAL MODELING OF ADVANCED SEMICONDUCTOR-DEVICES FROM THE PHYSICAL POINT-OF-VIEW

A new two-dimensional hydrodynamic model for heterostructure semicondu ctors has been derived under the assumption of nonparabolic energy ban ds. The governing equations have been obtained from the first three mo ments of the Boltzmann transport equation. No specified carrier energy distribution function is needed and the model accounts for degeneracy . The relaxation time model has been applied to the Boltzmann collisio n integral and the isothermal approximation is assumed for the lattice . Transport equations of lower level of sophistication are easily obta ined from this hydrodynamic model. The transport equations coupled to Poisson's equation have been discretized by using a generalization of the finite difference scheme, the box integration method. To achieve g ood accuracy and stability, the current density and the energy flux de nsity are discretized by a scheme resembling the Scharfetter-Gummel ap proach. Material parameters for Si, Ge, alpha SiC, beta SiC, diamond a nd Si1-xGex together with new as well as conventional physical models are presented. Simulation of advanced semiconductor devices, i.e., bal listic Si diode, Si1-xGex/Si HBT, power diamond diode, vertical diamon d power JFET and lateral diamond power MESFET, has been performed.