Low specific contact resistivity to graphene achieved by AuGe/Ni/Au and annealing process

Low metal-graphene contact resistance is important in making high-performance graphene devices. In this work, we demonstrate a lower specific contact resistivity of Au_0.88 Ge_0.12/Ni/Au-graphene contact compared with Ti/Au and Ti/Pt/Au contacts. The rapid thermal annealing process was optimized to improve AuGe/Ni/Au contact resistance. Results reveal that both pre- and post-annealing processes are effective for reducing the contact resistance. The specific contact resistivity decreases from 2.5×10^-4 to 7.8×10^-5 Ω·cm² by pre-annealing at 300℃ for one hour, and continues to decrease to 9.5×10^-7 Ω·cm² after post-annealing at 490℃ for 60 seconds. These approaches provide reliable means of lowering contact resistance.