100-nm T-gate InAlAs/InGaAs InP-based HEMTs with f_T=249 GHz and f_max=415 GHz

InAlAs/InGaAs high electron mobility transistors (HEMTs) on an InP substrate with well-balanced cutoff frequency f_T and maximum oscillation frequency f_max are reported. An InAlAs/InGaAs HEMT with 100-nm gate length and gate width of 2×50 μm shows excellent DC characteristics, including full channel current of 724 mA/mm, extrinsic maximum transconductance g_m.max of 1051 mS/mm, and drain–gate breakdown voltage BV_DG of 5.92 V. In addition, this device exhibits f_T=249 GHz and f_max=415 GHz. These results were obtained by fabricating an asymmetrically recessed gate and minimizing the parasitic resistances. The specific Ohmic contact resistance was reduced to 0.031 Ω·mm. Moreover, the f_T obtained in this work is the highest ever reported in 100-nm gate length InAlAs/InGaAs InP-based HEMTs. The outstanding g_m.max, f_T, f_max, and good BV_DG make the device suitable for applications in low noise amplifiers, power amplifiers, and high speed circuits.