▎ 摘　　要

NOVELTY - A seamless hexagonal boron nitride atomic monolayer thin film has a pseudo-single crystal structure having boron nitride grains seamlessly merged. Each of the grains has a dimension of 10-1000 mu m. USE - Seamless hexagonal boron nitride atomic monolayer thin film is used for fabricating graphene device. ADVANTAGE - The seamless hexagonal boron nitride atomic monolayer thin film has reduced defects, and is manufactured with improved productivity. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for fabrication of seamless hexagonal boron nitride atomic monolayer thin film, which involves pre-annealing a metal thin film at a temperature (t1) in a chamber while supplying hydrogen gas to the chamber, supplying nitrogen source gas and boron source gas to the chamber, and forming the seamless hexagonal boron nitride atomic monolayer thin film by annealing the pre-annealed metal thin film at a temperature (t2).