Nitride semiconductor light-emitting device and method of manufacturing the same
A nitride semiconductor light-emitting device including a reflecting layer made of a dielectric material, a transparent conductive layer, a p-type nitride semiconductor layer, a light emitting layer and an n-type nitride semiconductor layer in this order and a method of manufacturing the same are provided. The transparent conductive layer is preferably made of a conductive metal oxide or an n-type nitride semiconductor, and the reflecting layer made of a dielectric material preferably has a multilayer structure obtained by alternately stacking a layer made of a dielectric material having a high refractive index and a layer made of a dielectric material having a low refractive index.
1. A nitride semiconductor light-emitting device comprising:
a reflecting layer, a transparent conductive layer, and a nitride semiconductor layer including a p-type nitride semiconductor layer, a light emitting layer and an n-type nitride semiconductor layer in this order,
wherein said reflecting layer includes a layer having a smaller critical angle of total reflection than said transparent conductive layer at an interface with the transparent conductive layer, and
wherein said layer having a smaller critical angle of total reflection than said transparent conductive layer has a through-port passing therethrough in a thickness direction in a region located immediately under said transparent conductive layer.
2. The nitride semiconductor light-emitting device according to claim 1 , wherein said layer having a smaller critical angle of total reflection than said transparent conductive layer is made of SiO 2 .
3. The nitride semiconductor light-emitting device according to claim 1 , wherein said transparent conductive layer is made of a conductive metal oxide.
4. The nitride semiconductor light-emitting device according to claim 1 , wherein said transparent conductive layer is made of an n-type nitride semiconductor.
5. The nitride semiconductor light-emitting device according to claim 1 , wherein said reflecting layer has a reflectance of 80 to 100% with respect to light emitted from said light emitting layer.
6. The nitride semiconductor light-emitting device according to claim 1 , wherein a first surface of the nitride semiconductor layer provided with said reflecting layer is planar.
7. The nitride semiconductor light-emitting device according to claim 1 , wherein
a second surface of the nitride semiconductor layer opposite to a first surface of the nitride semiconductor layer is irregularized.
8. The nitride semiconductor light-emitting device according to claim 1 , wherein
a length of said transparent conductive layer in a direction perpendicular to a thickness direction is smaller than a length of said p-type nitride semiconductor layer in a direction perpendicular to a thickness direction, and
said reflecting layer is in contact with side surfaces of said transparent conductive layer and a surface of said transparent conductive layer closer to said reflecting layer and further in contact with a part of a surface of said p-type nitride semiconductor layer closer to said transparent conductive layer, said part of a surface being not in contact with said transparent conductive layer.
9. The nitride semiconductor light-emitting device according to claim 1 , wherein a thickness of said reflecting layer is 0.2 to 5 μm.
10. The nitride semiconductor light-emitting device according to claim 1 , further comprising:
a support substrate,
wherein said support substrate, said reflecting layer, said transparent conductive layer, said p-type nitride semiconductor layer, said light emitting layer, and said n-type nitride semiconductor layer are disposed in this order.
11. The nitride semiconductor light-emitting device according to claim 10 , further comprising:
a eutectic bonding layer having a single- or multilayer structure made of a metal including a eutectic bonding metal or an alloy containing said metal between said support substrate and said reflecting layer.
12. The nitride semiconductor light-emitting device according to claim 11 , further comprising:
an adhesion layer between said reflecting layer and said eutectic bonding layer.
13. The nitride semiconductor light-emitting device according to claim 10 , wherein said support substrate is a substrate made of a plated metal or alloy.
14. A method of manufacturing the nitride semiconductor light-emitting device according to claim 10 , the method comprising:
(A) stacking said n-type nitride semiconductor layer, said light emitting layer, and said p-type nitride semiconductor layer on a growth substrate in this order;
(B) forming said transparent conductive layer on the surface of said p-type nitride semiconductor layer;
(C) forming said reflecting layer on an exposed surface of an obtained laminate;
(D) stacking said support substrate;
(E) removing said growth substrate; and
(F) obtaining a plurality of nitride semiconductor light-emitting devices by performing chip division.
15. The method of manufacturing the nitride semiconductor light-emitting device according to claim 14 , further comprising:
(G) partially exposing said transparent conductive layer by forming a through-port passing through said reflecting layer in the thickness direction in said reflecting layer after step (C).
16. The method of manufacturing the nitride semiconductor light-emitting device according to claim 15 , wherein said through-port is formed by etching and said transparent conductive layer functions as an etching stopper layer in step (G).
17. The method of manufacturing a nitride semiconductor light-emitting device according to claim 14 , further comprising:
(H) exposing said reflecting layer by forming recesses substantially at a constant interval from a side of said n-type nitride semiconductor layer between steps (E) and (F).
18. The method of manufacturing a nitride semiconductor light-emitting device according to claim 17 , wherein said chip division is performed on positions on bottom surfaces of said recesses in step (F).
19. The method of manufacturing a nitride semiconductor light-emitting device according to claim 14 , further comprising:
(I) irregularizing a surface of said n-type nitride semiconductor layer after step (E).
20. A nitride semiconductor light-emitting device comprising:
a reflecting layer, a transparent conductive layer, and a nitride semiconductor layer including a p-type nitride semiconductor layer, a light emitting layer, and an n-type nitride semiconductor layer in this order,
wherein said reflecting layer includes a layer having a smaller critical angle of total reflection than said transparent conductive layer at an interface with the transparent conductive layer side, and
wherein said p-type nitride semiconductor layer includes a current blocking region formed in contact with said transparent conductive layer.
21. The nitride semiconductor light-emitting device according to claim 20 , wherein
said reflecting layer has a through-port passing through said reflecting layer in a thickness direction in a region located immediately under said transparent conductive layer, and
said through-port provided in said reflecting layer is positioned immediately under said current blocking region.
22. A nitride semiconductor light-emitting device comprising:
a growth substrate, an n-type nitride semiconductor layer, a light emitting layer, a p-type nitride semiconductor layer, a transparent conductive layer, and a reflecting layer in this order,
wherein said reflecting layer includes a layer having a smaller critical angle of total reflection than said transparent conductive layer at an interface with the transparent conductive layer, and
wherein said layer having a smaller critical angle of total reflection than said transparent conductive layer has a through-port passing therethrough in a thickness direction in a region located immediately under said transparent conductive layer.
23. The nitride semiconductor light-emitting device according to claim 22 , wherein said growth substrate is a sapphire substrate having an irregularized surface.