Controlled and selective area growth of monolayer graphene on 4H-SiC substrate by electron-beam-assisted rapid heating

Abstract

A facile method for direct and selective area conversion of 4H-SiC substrates into homogeneous epitaxial graphene is demonstrated by the irradiation of a low energy (5 keV) electron beam (e-beam). The localized interactions like scattering, excitation, and ionization between the primary electrons and the SiC surface result in Si-C bond breaking, and the excess kinetic energy of electrons is dissipated as heat that results in the selective sublimation of the Si ion favoring the formation of epitaxial graphene. The thickness of the graphene layer is precisely controlled by varying the e-beam energy and the irradiation time. The number of graphene layers increases with irradiation due to thermally induced Si sublimation over the depth of a few atomic layers depending on the incident energy of the e-beam. The Hall mobility of large area single layer graphene formed on the Si-face is ∼6450 cm 2V-1s-1 with a surface carrier density (n-type) of 1.5 × 1013 cm-2. Our results demonstrate that the e-beam irradiation technique is a viable route to define wafer scalable selective area graphene structures directly on semi-insulating 4H-SiC substrates for electronic applications. © 2013 American Chemical Society.