COMPARISON OF SIC, GAAS, AND SI-R-F-MESFET POWER DENSITIES

The maximum power density of Si, GaAs, and 4H-SiC MESFET's was modeled using material parameters, a planar MESFET cross section, and a piecewise linear MESFET drain characteristic. The maximum power density for the Si, GaAs, and 4H-SiC was calculated to be 0.45 W/mm, 0.78 W/mm, and 17.37 W/mm at drain voltages of 8.4 V, 8.3 V, and 105 V, respectively. Modeling power density as a function of drain voltage showed that, for low voltage applications, the GaAs MESFET has the highest power density because of its high electron mobility and very low channel resistance (R(on)). For high voltage applications, the 4H-SiC MESFET has the highest absolute power density because of the higher breakdown voltage of this material. Experiment data agree qualitatively with the modeled results.