LED CHIP HAVING COMPOSITE DIAMOND SUBSTRATE AND PREPARATION METHOD THEREFOR

Disclosed are an LED chip having a composite diamond substrate and a preparation method therefor. The LED chip comprises a composite diamond substrate and an LED epitaxy grown thereon, wherein the composite diamond substrate comprises a diamond base, and a diamond buffer layer generated on the diamond base and comprising a diamond transition layer located on the diamond base and a boron-doped diamond thin film layer grown on the diamond transition layer. By forming, on a diamond base, a composite diamond substrate comprising a diamond transition layer and a boron-doped diamond thin film layer, the epitaxy of an LED chip can be grown with high quality on the composite diamond substrate. The shortcoming of poor heat dissipation performance of a common sapphire substrate can be overcome, and the defects such as crystal lattice dislocation during an epitaxy growth process can also be overcome. Furthermore, by forming a patterned graphene layer on the composite diamond substrate, the performance of the prepared LE