Light-emitting device and manufacturing method thereof

A light emitting diode (LED), including: a substrate having an upper surface, a lower surface and a plurality of side surfaces; and a semiconductor stack formed on the upper surface; wherein one of the plurality of side surfaces includes: a first region adjacent to the upper surface and having a first roughness; a second region having one or a plurality of textured areas substantially parallel to the upper surface and/or the lower surface, wherein one of the textured areas having a second roughness and; and a third region between the first region and the second region or/and the plurality of textured areas and having a third roughness; wherein the first roughness is not greater than the second roughness and the third roughness is less than the first roughness; and a thickness of the substrate is between 150 and 250 [mu]m.