188 GHz doped-channel In 0.8 Ga 0.2 P/In 0.53 Ga 0.47 As/InPHFETs

The authors have fabricated 0.14 µm T-gate, doped-channel In0.8Ga0.2P/In0.53Ga0.47As/InP HFETs. An extrinsic peak transconductance of 722 mS/mm and a maximum current density of 761 mA/mm were obtained. The doped-channel HFET exhibits excellent RF performance with fT = 188 GHz and fmax = 225 GHz at Vds = 1.5 V. These are state-of-the-art results for doped-channel HFETs, and are comparable to the best reported performance of InP p-HEMTs with similar gate length.