Comparison of InGaP/InGaAs/GaAs and InGaPtInGaAs/AlGaAs pseudomorphic high electron mobility transistors

Abstract

We have studied the DC and RF characteristics of InGaP/InGaAs/AlGaAs and InGaP/InGaAs/GaAs pseudomorphic high electron mobility transistors (PHEMTs). The InGaP gate barrier provides adequate carrier confinement for the channel carriers and at the same time eliminates the problems associated with AlGaAs. Excellent device performance was obtained for both types of devices. No short channel effect was observed at a gate length as low as 0.3 mum. The InGaP/InGaAs/AlGaAs PHEMTS are superior in that they have higher transconductance, higher current carrying capability and better RF performance. This is attributed to the better carrier confinement at the back channel. These results demonstrate that InGaP/InGaAs/AlGaAs PHEMTs are favorable candidates for microwave applications.