Abstract: An epitaxial structure having a low defect density includes: a base layer; a first epitaxial layer having a plurality of concentrated defect groups, and an epitaxial surface that has a plurality of first recesses corresponding in position to the concentrated defect groups, the sizes of the first recesses being close to each other; and a plurality of defect-termination blocks respectively and filling the first recesses and having polished surfaces. The defect-termination blocks are made of a material which is different in removal rate from that of the first epitaxial layer.

Abstract: An epitaxial structure having a low defect density includes: a base layer; a first epitaxial layer having a plurality of concentrated defect groups, and an epitaxial surface that has a plurality of first recesses corresponding in position to the concentrated defect groups, the sizes of the first recesses being close to each other; and a plurality of defect-termination blocks respectively and filling the first recesses and having polished surfaces. The defect-termination blocks are made of a material which is different in removal rate from that of the first epitaxial layer.

Abstract: A method of making an epitaxial structure includes: (a) forming laterally a first epitaxial layer on a base layer, the first epitaxial layer having an epitaxial surface; (b) etching the first epitaxial layer using a wet etching agent so that the epitaxial surface has a plurality of first recesses; (c) depositing on the first epitaxial layer a defect-termination layer; and (d) removing the defect-termination layer by a chemical mechanical polishing process, thereby forming a plurality of defect-termination blocks that respectively and fill the first recesses, wherein the defect-termination blocks have polished surfaces that are substantially flush with the epitaxial surface.