Temperature-dependent small-signal and power and noise characterization of GaAs power FETs

We present a complete on-wafer characterization of a GaAs power MESFET (L/sub g/=0.6 /spl mu/m, W/sub g/=300 /spl mu/m) at various temperature of operation. DC-IV, small-signal, power and noise parameters measurements are achieved at temperatures from 18 K to 300 K. The transition between small-signal and large-signal mode of operation is studied, highlighting the importance of load-pull measurements, and the caution that must be considered when applying small-signal results to large-signal mode of operation. Power measurements were achieved at an optimal bias condition to take into account the positive Temperature Coefficient (TC) that the On Breakdown Voltage exhibits. Results demonstrate performance improvements, when the device operates at reduced lattice temperature, in output power, power-added efficiency, intermodulation products and noise parameters. This analysis technique provides a path for developing robust temperature dependent large-signal models.