Growth of High Quality Epitaxial Graphene on Hexagonal SiC Surface with Molybdenum Plate Capping during UHV Annealing

Abstract

It was found that high quality epitaxial graphene (EG) films can be grown on hexagonal SiC surface at relatively low temperature ~900°C simply by capping the surface with a molybdenum plate (Mo-plate) during UHV annealing. The enhanced crystallinity of the EG films grown with Mo-plate capping was confirmed by Raman spectrum measurements, compared with the films grown without Mo-plate capping. Mo-plate capping is believed to induce heat accumulation on SiC surface in contact with it by thermal radiation mirroring and slow down Si atom sublimation from surface effectively, which establish an environment favorable to grow high quality EG films cooperatively.[1] A top-gated field effect transistor (FET) using an EG film grown on Si-face semi-insulating 6H-SiC surface as a channel material was fabricated. The FET on/off ratio was measured to be ~4.6 and the field effect mobility of EG be ~1800 cm2/Vs, higher than the values reported in other researches so far.