Effects of surface passivation and temperature on AlGaAs/InGaAs high-electron mobility transistor

Abstract

The effects of surface passivation on AlGaAs/InGaAs/GaAs HEMTs using silicon nitride are presented. The passivated HEMT exhibited stable operation at elevated temperatures up to 480 K with excellent pinch-off characteristics. Furthermore, the interesting and anomalous dependence of the two-terminal gate–drain breakdown voltage on temperature is investigated. The high-speed performance of the SiNX-passivated HEMT with an fT = 20.1 GHz and an fmax = 28.5 GHz is confirmed. The experimental results also demonstrate that the addition of a SiNX passivation layer to the AlGaAs/InGaAs/GaAs HEMTs increases the three-terminal on-state and off-state breakdown voltages and increases the cutoff frequency.