High efficiency light emitting diode and method for fabricating the same
View Patent ↗A high-efficiency light emitting diode including: a semiconductor stack positioned on a support substrate, including a p-type compound semiconductor layer, an active layer, and an n-type compound semiconductor layer; an insulating layer disposed in an opening that divides the p-type compound semiconductor layer and active layer; a transparent electrode layer disposed on the insulating layer and the p-type compound semiconductor layer; a reflective insulating layer covering the transparent electrode layer, to reflect light from the active layer away from the support substrate; a p-electrode covering the reflective insulating layer; and an n-electrode is formed on top of the n-type compound semiconductor layer. The p-electrode is electrically connected to the transparent electrode layer through the insulating layer.
1. A light emitting diode (LED) comprising:
a support substrate;
a semiconductor stack disposed on the support substrate, the semiconductor stack comprising:
a first compound semiconductor layer having an upper surface and comprising first protrusions disposed on the upper surface;
a second compound semiconductor layer;
an active layer disposed between the first compound semiconductor layer and the second compound semiconductor layer; and
at least one opening that extends through the second compound semiconductor layer and the active layer, and exposes a portion of the first compound semiconductor layer, the portion facing the substrate;
an insulating layer disposed on the exposed portion of the first compound semiconductor layer and a sidewall of the at least one opening;
an electrode structure electrically connected to the second compound semiconductor layer and extending outside of the semiconductor stack; and
an electrode pad disposed the outside of the semiconductor stack and on the electrode structure.
2. The light-emitting diode of claim 1 , wherein the electrode structure comprises:
an electrode layer disposed on the insulating layer and contacting the second compound semiconductor layer; and
a first electrode disposed on the electrode layer.
3. The light-emitting diode of claim 2 , wherein the electrode layer comprises a metal or a conductive metal oxide.
4. The light-emitting diode of claim 2 , wherein the electrode layer comprises at least one of Ni, Au, indium tin oxide (ITO), ZnO, Ag, Pt, Pd, and Rh.
5. The light-emitting diode of claim 2 , further comprising a reflective layer disposed between the electrode layer and the first electrode.
6. The light-emitting diode of claim 5 , wherein the reflective layer comprises at least one material selected from the group consisting of Al, Ag, Si, Ti, Ta, Nb, In, Sn, Si x O y N z , Ti x O y , Ta x O y and Nb x O y .
7. The light-emitting diode of claim 5 , wherein the reflective layer comprises through-holes, the first electrode extending through the through holes and contacting the second compound semiconductor layer.
8. The light-emitting diode of claim 1 , further comprising second protrusions comprising a dielectric material, the second protrusions being disposed on the first protrusions.
9. The light-emitting diode of claim 8 , wherein:
the first protrusions are generally pyramidal; and
the second protrusions are generally conical.
10. The light-emitting diode of claim 1 , wherein the support substrate comprises at least one of Si, SiC, AlN, Si—Al, and CuW.
11. The light-emitting diode of claim 1 , wherein the semiconductor stack comprises a plurality of the at least one opening arranged in a matrix.
12. The light-emitting diode of claim 1 , further comprising a second electrode disposed on the upper surface of the first compound semiconductor layer.
13. The light-emitting diode of claim 12 , wherein the second electrode is disposed on a lower surface of the first compound semiconductor layer.
14. The light-emitting diode of claim 12 , wherein the second electrode is disposed on a planar portion of the upper surface of the first compound semiconductor layer.
15. The light-emitting diode of claim 14 , wherein the second electrode is disposed above the first protrusions.
16. The light-emitting diode of claim 5 , wherein the reflective layer comprises a distributed Bragg reflector (DBR).
17. The light-emitting diode of claim 1 , wherein the first compound semiconductor layer comprises an N-type impurity; and
the second compound semiconductor layer comprises a P-type impurity.