Light-emitting diode chip with high light extraction and method for manufacturing the same

A method for manufacturing a light-emitting device, comprising:

• forming an epitaxial-layer structure for generating light by electro-optical effect on a first substrate, said epitaxial-layer structure having a first layer of first conductivity, a second layer of second conductivity and an active layer sandwiched between said first layer and said second layer;
• performing a first roughening step for roughening a top surface of said second layer;
• forming a pair of electrodes respectively in electrical contact with said first layer and said second layer;
• forming a provisional substrate separately on said second layer and removing said first substrate under said epitaxial-layer structure to expose a bottom surface of said first layer;
• performing a second roughening step for roughening the bottom surface of said first layer;
• forming a transparent refractive layer connecting to said first layer, said transparent refractive layer having a refractive index greater than that of the air and less than that of the epitaxial-layer structure;
• forming a second substrate including a mirror reflective layer connecting to said transparent refractive layer;
• and
• removing said provisional substrate,
• wherein the step of forming the second substrate comprises forming a seed layer on side and bottom surfaces of said transparent refractive layer and then performing an electroplating process to form the second substrate from said seed layer so that the reflective mirror layer has a U-shape surrounding said side and bottom surfaces of said transparent refractive layer.