Physical modelling of microwave field effect transistors: a review

The accurate modelling of GaAs FETs and related heterojunction structures requires that a number of physical phenomena and technological parameters be considered. Among these, electron dynamics in a two-dimensional gas, the influence of deep traps in substrates and AlGaAs layers, the source parasitic access impedance, surface potential effect, and velocity overshoot in submicrometer devices are of interest. A series of simulation models exist which can take a number of these effects into consideration in a more or less accurate way: the Monte Carlo or particle models, the two-dimensional solving methods for semiconductor equations, and the simpler one-dimensional or analytical models. These are reviewed and their main ranges of applicability are compared and discussed.<>