Atomic Layer Deposition Alumina-Mediated Graphene Transfer for Reduced Process Contamination

Herein, an approach for integrating gate insulator deposition and graphene transfer steps in the fabrication of graphene field-effect devices is reported. A thin layer of Al₂O₃ is deposited by atomic layer deposition (ALD) onto as-grown graphene on copper, where the improved surface wettability of graphene on copper aids in obtaining a uniform deposition of the ALD layer. The ALD Al₂O₃/graphene stack is then mechanically delaminated from the copper surface and transferred onto the desired target substrate. An ALD layer thickness between 20 and 30 nm is optimal for facilitating such transfer. The ALD layer protects graphene from process contamination during subsequent transfer and device fabrication, resulting in reduced doping in measured field-effect devices.