US Patent 7834368 Light-emitting diode having additional stack structure

A light-emitting diode includes a substrate, a primary stack structure, a secondary stack structure, a transparent insulating material and a transparent conducting layer in an embodiment. Each of the primary and the secondary stack structure has a first conducting-type semiconductor layer, and illuminating layer, and a second conducting-type semiconductor layer sequentially formed on the substrate, wherein plural pillar-like holes are formed at the top surface of the second conducting-type semiconductor layer of the secondary stack structure and protrude into the first conducting-type semiconductor layer of the secondary stack structure. The transparent insulating material is filled into the holes. The transparent conducting layer is coated on the primary stack structure, the transparent insulating material, and the tope surface of the second conducting-type semiconductor layer of the secondary stack structure.