The electrical properties of a GaAs FET having a practical doping density and having a quarter-micrometer source-drain distance and a quarter-micrometer gate length have been studied by two-dimensional Monte Carlo particle simulation.

mA/20µm,

mS/mm, and

GHz are predicted. The reasons for the high performances are discussed in terms of the electron dynamics in the device. The current saturation mechanism and the current control mechanism of the FET are made clear.