Global modeling of carrier-field dynamics in semiconductors using EMC-FDTD

The interactions between carriers and fields in semiconductors at low frequencies (<100 GHz) can be adequately described by numerical solution of the Boltzmann transport equation coupled with Poisson's equation. As the frequency approaches the THz regime, the quasi-static approximation fails and full-wave dynamics must be considered. Here, we review recent advances in global modeling techniques-numerical techniques that couple carrier dynamics with full wave dynamics. We focus on the coupling between the stochastic ensemble Monte Carlo (EMC) simulation of carrier transport and the finite-difference time-domain (FDTD) solution to Maxwell's curl equations. We discuss the stability and accuracy requirements for different types of high-frequency excitation (wave illumination vs. ac bias), and present simulation results for the THz-regime conductivity of doped bulk silicon, ultrafast carrier dynamics and radiation patterns in GaAs filaments, and the ac response of GaAs MESFETs.