50-nm T-gate metamorphic GaAs HEMTs with fT of 440 GHz and noise figure of 0.7 dB at 26 GHz

GaAs-based transistors with the highest f_T and lowest noise figure reported to date are presented in this letter. A 50-nm T-gate In_0.52Al_0.48As/In_0.53Ga_0.47As metamorphic high-electron mobility transistors (mHEMTs) on a GaAs substrate show f_T of 440 GHz, f_max of 400 GHz, a minimum noise figure of 0.7 dB and an associated gain of 13 dB at 26 GHz, the latter at a drain current of 185 mA/mm and g_m of 950 mS/mm. In addition, a noise figure of below 1.2 dB with 10.5 dB or higher associated gain at 26 GHz was demonstrated for drain currents in the range 40 to 470 mA/mm at a drain bias of 0.8 V. These devices are ideal for low noise and medium power applications at millimeter-wave frequencies.