EPITAXIAL STRUCTURE OF SEMICONDUCTOR DEVICE, PREPARATION METHOD THEREFOR, AND SEMICONDUCTOR DEVICE

Embodiments of the present invention discloses an epitaxial structure of a semiconductor device, a preparation method therefor, and a semiconductor device. The epitaxial structure comprises a substrate, a nucleation layer and a buffer layer. The nucleation layer is located on one side of the substrate. The nucleation layer comprises a plurality of island-like nucleation units. The surfaces of the nucleation units on the sides close to the substrate are communicated with each other, and the surfaces of the nucleation units on the sides away from the substrate are separated from each other. The buffer layer is located on the side of the nucleation layer away from the substrate. The buffer layer comprises a 3D buffer layer, and the 3D buffer layer is formed on the surface of the side of the nucleation layer away from the substrate. By means of the technical solution of the embodiments of the present invention, the quality of the epitaxial structure is improved, and thus the quality of the semiconductor device is