Precision cutting and patterning of graphene with helium ions

Abstract

We report nanoscale patterning of graphene using a helium ion microscope configured forlithography. Helium ion lithography is a direct-write lithography process, comparableto conventional focused ion beam patterning, with no resist or other materialcontacting the sample surface. In the present application, graphene samples onSi/SiO2 substrates are cut using helium ions, with computer controlled alignment,patterning, and exposure. Once suitable beam doses are determined, sharp edgeprofiles and clean etching are obtained, with little evident damage or doping to thesample. This technique provides fast lithography compatible with graphene, with∼15 nm feature sizes.