Nanogate InP-HEMT technology for ultrahigh-speed performance

We succeeded in fabricating decananometer-gate InGaAs/InAlAs high electron mobility transistors (HEMTs) with extremely high current gain cutoff frequencies (f_T´s) of up to 562 GHz. The superior high-speed performance was obtained through laterally scaling the gate length (L_g) and the gate-recess length, introducing a double recessed cap structure, and vertically scaling the gate-channel distance. We investigated the effect of these structures on the high-frequency performance, and clarified their advantages for the ultrahigh-speed operation from the view point of enhanced electron overshoot velocity, reduced parasitic source and drain resistances, and suppressed short channel effect.