▎ 摘　　要

NOVELTY - Preparation of gallium nitride epitaxial structure comprises providing a silicon carbide substrate, pre-processing, growing a graphene film, growing diamond film, growing aluminum nitride polycrystalline film, annealing to grow into aluminum nitride single crystal nucleus, growing a three-dimensional aluminum nitride buffer layer, growing a gallium nitride buffer layer, growing a graded composition aluminum gallium nitride barrier layer, and growing gallium nitride cap layer. USE - The method is for preparation of gallium nitride epitaxial structure. ADVANTAGE - The method uses graphene and diamond as fast thermal conductive layer, and has thin gallium nitride buffer layer that greatly shortens the heat transmission distance of radio frequency device, effectively reduce the working thermal resistance and improve the working efficiency of HEMT device.