High-performance 0.1-μm In/sub 0.4/AlAs/In/sub 0.35/GaAs MHEMTs with Ar plasma treatment

High-performance 0.1-μm In/sub 0.4/AlAs/In/sub 0.35/GaAs metamorphic high-electron mobility transistors (MHEMTs) on GaAs substrate have been successfully fabricated with Ar plasma treatment. Before the gate Schottky metallization, the devices were treated with Ar plasma, which might clean and improve the surface of exposed barrier layer. The devices fabricated with Ar plasma treatment exhibited the excellent characteristics such as 50% reduction of the reverse gate leakage currents, the improved Schottky ideality factor of 1.37, high extrinsic transconductance of 700 mS/mm, and high maximum drain current density of 780 mA/mm. And the cutoff frequency f_T as high as 210 GHz was achieved. To our knowledge, this is the best reported cutoff frequency for a 0.1-μm MHEMT with an indium content of 35% in the channel.