RF Performance Improvement of Metamorphic High-Electron Mobility Transistor Using (InxGa1-xAs)(m)/(InAs)(n) Superlattice-Channel Structure for Millimeter-Wave Applications

Abstract

High-performance metamorphic high-electron mobility transistors (MHEMTs) using an (InxGa1-xAs)(m)/(InAs)(n) superlattice structure as a channel layer have been fabricated successfully. These HEMTs with 80-nm gate length exhibited a high drain current density of 392 mA/mm and a transconductance of 991 mS/mm at 1.2-V drain bias. Compared with a regular InxGa1-xAs channel, the superlattice-channel HEMTs showed an outstanding performance due to the high electron mobility and better carrier confinement in the (InxGa1-xAs)(m)/(InAs)(n) channel layer. When biased at 1.2 V, the current gain cutoff frequency (f(T)) and the maximum oscillation frequency (f(max)) were extracted to be 304 and 162 GHz, respectively. As for noise performance, the device demonstrated a 0.75-dB minimum noise figure(NFmin) with an associated gain of 9.6 dB at 16 GHz. Such superior performance has made the devices with a superlattice channel well suitable for millimeter-wave applications.