Channel-composition-dependent characteristics of δ-doped In _xAl_1-xAs/In_yGa_1-yAs metamorphic high electron mobility transistors

This work provides comprehensive comparisons of the device characteristics, including the voltage gain, power performance, linearity and noise characteristics, for InAlAs/InGaAs/GaAs metamorphic high electron mobility transistors with respect to different indium contents in the InGaAs channel. Though the device with a high In-ratio InGaAs channel usually demonstrated improved high-frequency characteristics, the kink effects in their narrow-gap channel materials were found to seriously degrade the device performance. On the other hand, the low In-ratio channel device had characteristics advantageous for high-gain and high-linearity applications while the device with a compromised channel composition design was suitable for high-power circuit applications.