Hydroxyl-free buffered dielectric for graphene field-effect transistors

Abstract

Deposition of high quality dielectrics onto graphene is of significant challenge because of the chemically inert surface of the two-dimensional carbon lattice which cannot provide nucleating sites for high-κ oxide insulators. Here we utilize an ultrathin hydroxyl-free organic film, the benzocyclobutene (BCB) polymer, as a buffer layer between graphene and high-κ dielectrics in top-gate graphene transistors. By electrical measurements and Raman spectra, it has been demonstrated that the BCB-buffered dielectric stack does not significantly impact the electrical characteristics and doping level of graphene channel, allowing for high carrier mobility to be maintained in top-gate operation. Moreover, the application of the hydroxyl-free buffered dielectrics could remarkably decrease the density of interface state, and then suppress the hysteresis in graphene transistors, which is desirable for high performance graphene electronics.