0.12-μm gate III-V nitride HFET's with high contact resistances

HFET's with 0.12-μm gate length were fabricated on a III-V nitride wafer. The contact resistance from unannealed Ti/Au ohmic contact was 10 /spl Omega//spl middot/mm. Even with this relatively high contact resistance, f
_T
of 46.9 GHz and f
_max
of 103 GHz were measured with the Ti/Au contacts, the highest yet achieved on III-V nitride FETs. The improvement in the frequency response was mainly due to the decrease in the gate length (0.12 μm). In addition, the effects of high contact resistances at high frequency are discussed.