Abstract

In this paper,we review advanced III-V HEMT device technologies for millimetre-wave applications,particularly targeted above 100 GHz.We demonstrate performance advantages in moving to self- aligned T-gate strategies in lattice matched InP HEMTs. For 120 nm gate lengths,we have obtained self-aligned, non-annealed Ohmic contact devices with gm of 1450 mS/mm,fT of 220 GHz and fmax of 435 GHz.We will also present data on a high yield 50 nm T-gate process in the metamorphic GaAs material system utilizing non-selective digital wet etching with performance metrics including gm of 1500 mS/mm and fT of 350 GHz,to our knowledge,the fastest GaAs-based transistors reported to date.