Abstract

By combining high resolution electron beam lithography,novel T-gate resist stacks,aggressively scaled vertical architectures and highly uniform,reproducible non-elective single “digital ” gate recess etching techniques,we show it is possible to realise 50 nm gate length GaAs pHEMTs with fT of 200 GHz suitable for applications beyond 100 GHz.This shows that by properly optimising and controlling critical parameters in an aggressively scaled GaAs pHEMT technology,excellent mm-wave performance can be achieved without the need to move to metamorphic GaAs or InP HEMT solutions.