Simulation of the variation and sensitivity of GaAs MESFET large signal figures-of-merit due to process, material, parasitic, and bias parameters

A simulator for calculating MESFET large-signal figures of merit and their sensitivities with respect to various device design, material and operational parameters has been developed. A study of an ion-implanted device with a 0.42-μm gate length and 1.0-mm gate width is presented. The effects on maximum power-added efficiency, output power at the maximum power-added efficiency, and output power at 1-dB gain compression due to variation in implant peak doping density, implant range, implant straggle, gate length, gate width, and gate-drain breakdown voltage are presented. The data indicate that the device performance is most sensitive to changes in V_gdbd for values of V_gdbd less than 20 V. However, performance sensitivity goes to zero for V_gdbd greater than 20 V. RF performance is also sensitive to changes in the channel implant parameters. However, the simulated sensitivities are less than those for V_gdbd. Over fairly broad ranges, device performance is less sensitive to changes in L_g and W_g but degrades rapidly at the extrema