A light-emitting device including a substrate having a top surface, a side surface and a roughed surface between the top surface and the side surface, wherein the top surface includes a first portion and a second portion; a first semiconductor stack including a first upper surface and a first side wall, wherein the first semiconductor stack is on the second portion and exposes the first portion; a second semiconductor stack including a second side wall, wherein the second semiconductor stack is on the first upper surface and exposes an exposing portion of the first upper surface; wherein the first side wall and the first portion of the top surface form an acute angle α between thereof, and the second side wall and the exposing portion of the first upper surface form an obtuse angle β between thereof; and wherein the roughed surface is connected to the top surface.