▎ 摘　　要

NOVELTY - Planarizing irregularities in a surface of a graphene layer (3) formed on a substrate (1), comprises planarizing the graphene layer by removing graphene constituting a convex portion in the surface of the graphene layer by anisotropically etching the graphene layer using a plasma etching in an in-plane direction from an edge portion of the graphene. USE - The method is useful for planarizing irregularities in a surface of a graphene layer formed on a substrate (claimed) which is useful for making an electronic device. ADVANTAGE - The method: removes all of the convex portions so that the surface of the graphene layer is planarized without an atomic-level of irregularities, thus in the case where graphene is used for an electronic device, suppresses variations in device characteristics e.g. a transistor threshold value; suppresses damage to graphene sheets continuously extending downward from the graphene sheets that constitute the irregularities; performs plasma processing with less damage since the microwave plasma has a low electron temperature; and utilizes hydrogen plasma etching based on microwave plasma which increases etching rate by greater than or equal to 50 nm/minute. DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional process view of a graphene layer planarizing method. Substrate (1) Graphene layer (3) Workpiece (5)