Low specific contact resistivity to graphene achieved by AuGe/Ni/Au and annealing process**Project supported by the National Natural Science Foundation of China (Grant No. 61376065) and the Science and Technology Project of Suzhou, China (Grant No. ZXG2013044).

Abstract

Low metal–graphene contact resistance is important in making high-performance graphene devices. In this work, we demonstrate a lower specific contact resistivity of Au0.88Ge0.12/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 °C for one hour, and continues to decrease to 9.5 × 10−7 Ω·cm2 after post-annealing at 490 °C for 60 seconds. These approaches provide reliable means of lowering contact resistance.