Graphene Epitaxial Growth on SiC(0001) for Resistance Standards

A well-controlled technique for high-temperature epitaxial growth on 6H-SiC(0001) substrates is shown to allow the development of monolayer graphene that exhibits promise for precise metrological applications. Face-to-face and face-to-graphite annealing in a graphite-lined furnace at 1200 °C-2000 °C with a 101-kPa Ar background gas lowers the rates of SiC decomposition and Si sublimation/diffusion and thus provides a means to control the rate of graphene layer development. We studied a wide range of growth temperatures and times and describe the resulting sample surface morphology changes and graphene layer structures. The experimental results are compared to a kinetic model based on two diffusion processes: Si vapor diffusion in the Ar-filled gap and atomic diffusion through graphitic surface layers.