Facet extraction LED and method for manufacturing the same
A facet extraction LED improved in light extraction efficiency and a manufacturing method thereof. A substrate is provided. A light emitting part includes an n-type semiconductor layer, an active layer and a p-type semiconductor layer sequentially stacked on the substrate. A p-electrode and an n-electrode are connected to the p-type semiconductor layer and the n-type semiconductor layer, respectively. The p- and n-electrodes are formed on the same side of the LED. The light emitting part is structured as a ring.
1. A facet extraction light emitting diode comprising:
a substrate;
a light emitting stack including a n-type semiconductor layer, an active layer and a p-type semiconductor layer sequentially stacked on the substrate; and
a p-electrode and an n-electrode connected to the p-type semiconductor layer and the n-type semiconductor layer, respectively, wherein the p- and n-electrodes are formed on the same side of the diode,
wherein the light emitting stack comprises a ring structure having outer and inner facets, and the active layer has a ring shape in a plain view and is disposed in the ring structure.
2. The facet extraction light emitting diode according to claim 1 , wherein the ring structure has outer and inner facets crossing the active layer, the outer facet extracting a greater amount of light than the inner facet.
3. The facet extraction light emitting diode according to claim 1 , wherein each of the n-type semiconductor layer, the active layer and the p-type semiconductor layer comprises a group III-V compound semiconductor material.
4. A facet extraction light emitting diode comprising:
a substrate;
a light emitting stack including a n-type semiconductor layer, an active layer and a p-type semiconductor layer sequentially stacked on the substrate;
a p-electrode and an n-electrode connected to the p-type semiconductor layer and the n-type semiconductor layer, respectively, wherein the p- and n-electrodes are formed on the same side of the diode, wherein the light emitting stack comprises a ring structure; and
an anti-reflection film formed on the outer facet of the ring structure.
5. The facet extraction light emitting diode according to claim 4 , wherein the anti-reflection film has a reflectivity ranging from 0% to 5% with respect to light from the active layer.
6. A facet extraction light emitting diode comprising:
a substrate;
a light emitting stack including a n-type semiconductor layer, an active layer and a p-type semiconductor layer sequentially stacked on the substrate;
a p-electrode and an n-electrode connected to the p-type semiconductor layer and the n-type semiconductor layer, respectively, wherein the p- and n-electrodes are formed on the same side of the diode, wherein the light emitting stack comprises a ring; and
a reflective film formed on an inner facet of the ring structure.
7. The facet extraction light emitting diode according to claim 6 , wherein the reflective film has a reflectivity ranging from 90% to 100% with respect to light from the active layer.
8. The facet extraction light emitting diode according to claim 1 , wherein the ring structure has a circular outline.
9. The facet extraction light emitting diode according to claim 1 , wherein the ring structure has a polygonal outline.
10. The facet extraction light emitting diode according to claim 1 , comprising a flip-chip LED.
11. A facet extraction light emitting diode comprising:
a substrate;
a light emitting stack including a n-type semiconductor layer, an active layer and a p-type semiconductor layer sequentially stacked on the substrate; and
a p-electrode and an n-electrode connected to the p-type semiconductor layer and the n-type semiconductor layer, respectively,
wherein the p- and n-electrodes are formed on the same side of the diode, and the light emitting stack comprises a ring structure, and
wherein the ring structure satisfies a following relationship:
5 ≦W/L ≦10,000,
where L is a distance between the outer and inner facets, and W is an outer peripheral length of the active layer on the outer facet.
12. The facet extraction light emitting diode according to claim 1 , wherein the distance between the outer and inner facets of the ring structure ranges from 1 μm to 100 μm.
13. A facet extraction light emitting diode comprising:
a substrate;
a light emitting stack including a n-type semiconductor layer, an active layer and a p-type semiconductor layer sequentially stacked on the substrate;
a p-electrode and an n-electrode connected to the p-type semiconductor layer and the n-type semiconductor layer, respectively, wherein the p- and n-electrodes are formed on the same side of the diode, and the light emitting stack comprises a ring structure, and
wherein the ring structure has protrusions and indentations on the outer facet.
14. The facet extraction light emitting diode according to claim 1 , wherein the substrate comprises a sapphire substrate.
15. The facet extraction light emitting diode according to claim 1 , wherein the substrate comprises a conductive substrate.
16. The facet extraction light emitting diode according to claim 1 , wherein the conductive substrate comprises a GaN-based substrate.
17. A facet extraction light emitting diode comprising:
a substrate;
a light emitting stack including a n-type semiconductor layer, an active layer and a p-type semiconductor layer sequentially stacked on the substrate; and
a p-electrode and an n-electrode connected to the p-type semiconductor layer and the n-type semiconductor layer, respectively, wherein the p- and n-electrodes are formed on the same side of the diode, and the light emitting stack comprises a ring structure, and
wherein the n-electrode is surrounded by the ring structure.
18. The facet extraction light emitting diode according to claim 17 , wherein the n-electrode is disposed on the n-type semiconductor layer, surrounded by the ring structure.
19. The facet extraction light emitting diode according to claim 17 , wherein the substrate comprises a conductive substrate, and
wherein the n-electrode surrounded by the ring structure is in direct contact with the substrate.
20. A facet extraction light emitting diode comprising:
a substrate;
a light emitting stack including a n-type semiconductor layer, an active layer and a p-type semiconductor layer sequentially stacked on the substrate; and
a p-electrode and an n-electrode connected to the p-type semiconductor layer and the n-type semiconductor layer, respectively, wherein the p- and n-electrodes are formed on the same side of the diode, and the light emitting stack comprises a ring structure, and
wherein the outer and inner facets of the ring structure are inclined with respect to a stacking direction of the semiconductor layers in such a fashion that a distance between the outer and inner facets increases toward the substrate.
21. The facet extraction light emitting diode according to claim 1 , wherein the n- and p-type semiconductor layers and the active layer comprise a separate confinement heterostructure.