Modeling and characterization of ion-implanted GaAs MESFET's

Accurate modeling of GaAs IC's requires a good fit to the device characteristics over the entire range of gate and drain voltages. However, the existing circuit simulator models suitable for circuit simulation fail in the linear region of the current-voltage characteristics. In this paper, we demonstrate that the nonuniformity of the mobility and doping profiles strongly affects the linear region and propose an analytical model taking this nonuniformity into account. We also present the characterization techniques that relate the model parameters to the device physics and the fabrication methods. Excellent agreement with experimental data is obtained and the model is implemented into our GaAs IC circuit simulator.