SEMICONDUCTOR LIGHT EMITTING DEVICE

• US 20160329465A1
• Filed: 07/21/2016
• Published: 11/10/2016
• Est. Priority Date: 09/19/2008
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: WAKAI, Yohei, ONISHI, Masahiko
• Granted Patent: US 10,381,516 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A semiconductor light emitting device which includes at least one concave on a light extraction surface opposite to a surface on which a semiconductor stack comprising a light emitting layer between a n-type semiconductor layer and a p-type semiconductor layer is mounted. The concave has not less than two slopes each having a different slope angle in a direction that a diameter of the concave becomes narrower toward a bottom of the concave from an opening of the concave and a slope having a gentle slope angle is provided with irregularities and a slope having a steep slope angle is a flat surface.

Claims

1. A semiconductor light emitting device comprising:

a substrate;

a semiconductor stack including a p-type semiconductor layer, a light emitting layer, and an n-type semiconductor layer in this order from a substrate side; and

a passivation film on at least a part of the semiconductor stack,

wherein the n-type semiconductor layer has a light extraction surface including at least one concave structure,

wherein the concave structure has two slopes each having a different slope angle in a direction along which a diameter of the concave structure becomes narrower toward a bottom of the concave structure from an opening of the concave structure,

wherein one of the two slopes, having a gentler slope angle is provided with irregularities and the other of the two slopes, having a steeper slope angle is a flat surface,

wherein the passivation film, comprising an insulating material, covers the concave structure.

2. The semiconductor light emitting device according to claim 1, wherein the slope of the concave structure having the gentler slope angle is closer to the opening of the concave structure than the slope having the steeper slope angle.

3. The semiconductor light emitting device according to claim 1, wherein the concave structure has a bottom surface at the bottom and the bottom surface is provided with irregularities.

4. The semiconductor light emitting device according to claim 1, wherein a plurality of the concave structures are disposed on the light extraction surface, wherein adjacent openings of the plurality of the concave structures are separated from each other by a separating area, and wherein the separating area is provided with irregularities.

5. The semiconductor light emitting device according to claim 1, further comprising an electrode, wherein the electrode is disposed on the light extraction surface.

6. The semiconductor light emitting device according to claim 1, wherein a shape of the opening of the concave structure is a circle in plan view from the light extraction surface.

7. The semiconductor light emitting device according to claim 1, wherein a shape of the opening of the concave structure is a polygon in plan view from the light extraction surface.

8. The semiconductor light emitting device according to claim 1, wherein a shape of the opening of the concave structure is a hexagon in plan view from the light extraction surface.

10. The semiconductor light emitting device according to claim 1, wherein at least one of the slope having the gentler slope angle or the slope having the steeper slope angle of the concave structure is covered with the passivation film.

11. The semiconductor light emitting device according to claim 1, further comprising a p-electrode between the substrate and the p-type semiconductor layer, wherein the concave structure is disposed at a position facing the p-electrode.

15. The semiconductor light emitting device according to claim 4, wherein the slope of the concave structure having the gentler slope angle is closer to the opening of the concave structure than the slope having the steeper slope angle.

16. The semiconductor light emitting device according to claim 4, wherein the concave structure has a bottom surface at the bottom and the bottom surface is provided with irregularities.

17. The semiconductor light emitting device according to claim 4, further including an electrode on the light extraction surface.

18. The semiconductor light emitting device according to claim 4, wherein a shape of the opening of the concave structure is a circle in plan view from the light extraction surface.

9. A semiconductor light emitting device comprising:

a substrate;

a semiconductor stack including a p-type semiconductor layer, a light emitting layer, and an n-type semiconductor layer in this order from a substrate side; and

an electrode,

wherein the n-type semiconductor layer has a light extraction surface including at least one concave structure,

wherein the concave structure has two slopes each having a different slope angle in a direction along which a diameter of the concave structure becomes narrower toward a bottom of the concave structure from an opening of the concave structure,

wherein a slope having a gentle slope angle is provided with irregularities and a slope having a steep slope angle is a flat surface,

wherein a depth of the concave structure has a length not less than half of a thickness between the light extraction surface and the light emitting layer and less than the thickness between the light extraction surface and the light emitting layer, and

wherein the electrode is arranged directly on a light extraction surface.

12. The semiconductor light emitting device according to claim 9, wherein the slope of the concave structure having the gentler slope angle is closer to the opening of the concave structure than the slope having the steeper slope angle.

13. The semiconductor light emitting device according to claim 9, wherein the concave structure has a bottom surface at a bottom and the bottom surface is provided with irregularities.

14. The semiconductor light emitting device according to claim 9, wherein a shape of the opening of the concave structure is a circle in plan view from the light extraction surface.

19. The semiconductor light emitting device according to claim 9,

wherein the semiconductor stack has a higher planar portion outside the concave structure and a lower planar portion inside the concave structure,

wherein the two slopes connect the higher planar portion and the lower planar portion.

20. The semiconductor light emitting device according to claim 9,

wherein the concave structure is exposed to an outside of the semiconductor light emitting device.

21. The semiconductor light emitting device according to claim 19, wherein a plurality of the concave structures are disposed on the light extraction surface, wherein adjacent openings of the plurality of the concave structures are separated from each other, wherein a separating area which separates the adjacent openings is provided with irregularities, and wherein the separating area comprises the higher planar portion.

22. A semiconductor light emitting device comprising:

a substrate; and

a semiconductor stack including a p-type semiconductor layer, a light emitting layer, and an n-type semiconductor layer in this order from a substrate side,

wherein the n-type semiconductor layer has a light extraction surface including at least one concave structure,

wherein the concave structure includes a bottom surface and a sloped surface that is sloped in a direction along which a diameter of the concave structure becomes narrower toward the bottom surface from an opening of the concave structure,

wherein the light extraction surface includes a separating area that separates each of the concave structures, and

wherein the sloped surface of the concave structure is a flat surface, and the bottom surface of the concave structure and the separating area have irregularities.

23. The semiconductor light emitting device according to claim 22, wherein a passivation film, comprising an insulating material, is arranged on the light extraction surface so as to cover the concave structure.

24. The semiconductor light emitting device according to claim 22, further including an electrode, wherein the electrode is disposed on the light extraction surface.

25. The semiconductor light emitting device according to claim 22, wherein a shape of the opening of the concave structure is a circle in plan view from the light extraction surface.

26. The semiconductor light emitting device according to claim 22, wherein a shape of the opening of the concave structure is a polygon in plan view from the light extraction surface.

27. The semiconductor light emitting device according to claim 22, wherein a shape of the opening of the concave structure is a hexagon in plan view from the light extraction surface.

28. The semiconductor light emitting device according to claim 22, wherein a depth of the concave structure has a length not less than half of a thickness between the light extraction surface and the light emitting layer and less than the thickness between the light extraction surface and the light emitting layer.

29. The semiconductor light emitting device according to claim 22, further including a p-electrode between the substrate and the p-type semiconductor layer.