Gate-alloy-related kink effect for metamorphic high-electron-mobility transistors

摘要

Gate-metal-related kink effects in InAlAs/InGaAs/GaAs metamorphic high-electron-mobility transistors have been investigated. Improvements on the kink effect have been observed by using the higher Schottky barrier height gate alloys, including Ti/Au, Ni/Au, and Pt/Au, as compared to the use of the conventional Au gate metal. In comparison with gate alloy combinations, the devices with Ti/Au alloy exhibit superior noise characteristics, whereas those with Ni/Au alloy demonstrate the highest power characteristics. With the gate dimensions of 1.2×200 μm~(2), the device minimum noise figure, NF_(min), is 1.17 dB at 2.4 GHz by using Ti/Au and the output power is 13.14 dBm at 2.4 GHz by using Ni/Au. Significant rf characteristics have also been improved upon that with Au gate.