Investigation on electron and hole transport properties using the full-band spherical-harmonics expansion method

The full-band spherical-harmonics solution of the Boltzniann transport equation in silicon is achieved for both the conduction and valence band. The relevant scattering mechanisms (impact ionization, acoustic and optical phonons, ionized impurities) are modeled consistently. Comparison with Monte Carlo carrier-distribution functions at different electric fields emphasize the importance of a correct description of the band structure and scattering rates. The acoustic-phonon model is improved, the models of multiple collisions and impurity clustering, and the partial ionization of impurities are introduced. Comparison with experimental mobility data shows agreement over a wide range of temperatures and doping concentrations. Index Terms- Boltzniann equation, scattering mechanisms, semiconductor-device modeling, spherical-harmonics expansion. © 1998 IEEE.