Fabrication technology and device performances of ultra-short 30-nn-gate pseudomorphic In0.52Al0.48As/In0.75Ga0.25As HEMTs

In this paper, we succeed in fabricating ultra short 30 nm gate pseudomorphic high electron mobility transistors (HEMT) with excellent cutoff frequencies. Devices with smaller Schottky barrier layer exhibited a current gain cutoff frequency f
_T
of 450 GHz and a simultaneous maximum oscillation frequency f
_MAX
of 500 GHz. This performance can be attributed to the use of the two-step-recessed gate technology and the maintaining of high aspect ratio in our HEMTs.