A novel low-temperature passivation of InAlAs/InGaAs HEMT devices by MBE

The authors report the first successful passivation of an InAlAs/InGaAs/InP high electron mobility transistor (HEMT) with an InAlAs layer grown at low temperature (LT) by molecular beam epitaxy (MBE). After passivation, extrinsic transconductance, gate-drain breakdown voltage, and channel breakdown voltage are increased, while the gate leakage is reduced. RF measurement of the devices shows no degradation of the noise figure measured at 58 GHz. The authors report the result of a thermal storage test performed on the device at 230 degrees C with DC parameters monitored as a function of time. The results demonstrate that the LT passivation by MBE under ultra-high vacuum ambient is an effective novel approach to solve the problem inherent to surface-sensitive III-V devices, such as the HEMT devices reported here. >