Contact resistance in top-gated graphene field-effect transistors

The parasitic resistance of different source/drain metals for top-gated graphene field-effect transistors was extracted by fitting the measured ID-VG data with a resistance model and was found to be a significant part of the total resistance of graphene field-effect transistors. The results show that Ti/Au gives relatively large contact resistance, about 7500 Ω·μm. Ni/Au contact shows better result compared to Ti/Au, which is around 2100 Ω·μm. The lowest contact resistance was given by Ti/Pd/Au, which is around 750 Ω·μm. The contact resistivity for Ti/Pd/Au source/drain contact is around 2 × 10−6 Ω·cm2, close to state of the art GaAs technology.