Comparison of different carrier transport models for simulations of W-and D-band GaAs IMPATT diodes

This contribution presents a comparison of different carrier transport models for design and optimization of GaAs IMPATT diodes for W- and D-band applications. The drift-diffusion equations, an hydrodynamic transport model, a Monte-Carlo simulator and a Cellular-Automata code are considered. It is shown that the drift-diffusion equations cannot predict realistic output powers and dynamic impedances if doping profiles of the Read-type are examined. Secondly, the hydrodynamic transport model can closely reproduce the results of particle simulators if additional, slightly modified energy balance equations are solved in order to determine the ionization rates which higher accuracy compared to the standard model.