▎ 摘　　要

The diffusion barrier property of directly grown graphene-graphite films between Al2O3 films and Si substrates was evaluated using metalinsulator-semiconductor (MIS) structures. The roughness, morphology, sheet resistance, Raman spectrum, chemical composition, and breakdown field strength of the films were investigated after rapid thermal annealing. About 2.5-nm-thick graphene-graphite films effectively blocked the formation of the interfacial layer between Al2O3 films and Si, which was confirmed by the decreased breakdown field strength of graphene-graphite film structures. After annealing at 975 degrees C for 90 s, the increase in the mean breakdown field strength of the structure with the similar to 2.5-nm-thick graphene-graphite film was about 91% (from 8.7 to 16.6MV/cm), while that without the graphene-graphite film was about 187% (from 11.2 to 32.1MV/cm). Si atom diffusion into Al2O3 films was reduced by applying the carbon-based diffusion barrier. (C) 2016 The Japan Society of Applied Physics