Regular Paper In Situ Study on Oxygen Etching of Surface Buffer Layer on SiC(0001) Terraces

Thermal decomposition of SiC has been used for the fabrication of high quality monolayer graphene and graphene nanoribbons on semi-insulating substrates. In this work, we propose a selective oxygen etching method to remove buffer layers on SiC surfaces that are connected to monolayer graphene formed from step edges. A thermal treatment in an extreme low partial pressure oxygen diluted by argon atmosphere was found to be effective to etch only the buffer layers and remain monolayer graphene areas intact, which might be significant for the application of graphene to electric/spintronic devices. The etching processes of surface buffer layer investigated by in situ scanning electron microscopy and scanning tunneling microscopy revealed an etching rate dependence on a distance from a step edges, suggesting a distribution of crystallinity of surface buffer layer on a terrace. [DOI: 10.1380/ejssnt.2017.13]