Ultra-short 25-nm-gate lattice-matched InAlAs/InGaAs HEMTs within the range of 400 GHz cutoff frequency

We have succeeded in fabricating ultra-short 25-nm-gate InAlAs/InGaAs high electron mobility transistors (HEMTs) lattice-matched to InP substrates. The two-step-recessed gate technology and low temperature processing at below 300/spl deg/C allowed the fabrication of such ultra-short gates. DC measurements showed that the 25-nm-gate HEMT had good pinchoff behavior. We obtained a cutoff frequency f/sub T/ of 396 GHz, within the range of 400 GHz f/sub T/, for the 25-nm-gate HEMT. This f/sub T/ is the highest value get reported for any type of transistor, and the gate length of 25 nm is the shortest value ever reported for any compound semiconductor transistor that exhibits device operation.