▎ 摘　　要

We propose a damage-free formation method for high-quality gate dielectrics on epitaxial graphene (EG), which involves solution-based Al2O3 coating combined with microwave-assisted annealing (MW-sol-Al2O3). This method substantially preserves the pristine properties of EG with minimized hole doping and strain induction. The MW-sol-Al2O3 showed a surface roughness of similar to 0.237 nm and a dielectric constant of 7.5. A leakage current of 8.7 x 10(-6) A/cm(2), which is 3 orders of magnitude smaller than that of natural Al2O3 at the same electric field, was obtained. These excellent MW-sol-Al2O3 properties are ascribed to the effective elimination of hydroxyl-and carboxyl-related components from the film by microwave-assisted annealing. (c) 2017 The Japan Society of Applied Physics