RF Performance Improvement of Metamorphic High-Electron Mobility Transistor Using $(hbox{In}_{x}hbox{Ga}_{1 - x}hbox{As})_{m}/(hbox{InAs})_{n}$ Superlattice-Channel Structure for Millimeter-Wave Applications

摘要

High-performance metamorphic high-electron mobility transistors (MHEMTs) using an $(hbox{In}_{x}hbox{Ga}_{1 - x}hbox{As})_{m}/(hbox{InAs})_{n}$ 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 $hbox{In}_{x}hbox{Ga}_{1 - x}hbox{As}$ channel, the superlattice-channel HEMTs showed an outstanding performance due to the high electron mobility and better carrier confinement in the $(hbox{In}_{x}hbox{Ga}_{1 - x} hbox{As})_{m}/(hbox{InAs})_{n}$ 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 $(hbox{NF}_{min})$ 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.