Group III Nitride Semiconductor Light Emitting Device and Method for Producing the Same

• US 20100155754A1
• Filed: 02/13/2007
• Published: 06/24/2010
• Est. Priority Date: 02/16/2006
• Status: Active Grant

• Current Assignee: Sumitomo Chemical Company Limited
• Original Assignee: Sumitomo Chemical Company Limited
• Inventors: Kasahara, Kenji, Ueda, Kazumasa, Ono, Yoshinobu
• Granted Patent: US 8,097,891 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 33/025 Physical imperfections, e.g. particular concentration or distribution of impurities
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/42 Transparent materials

Abstract

The present invention provides a group III nitride semiconductor light emitting device and a method for producing the same. The group III nitride semiconductor light emitting device comprises (a1), (b1) and (c1) in this order: (a1) an N electrode, (b1) a semiconductor multi-layer film, (c1) a transparent electric conductive oxide P electrode, wherein the semiconductor multi-layer film comprises an N-type semiconductor layer, light emitting layer, P-type semiconductor layer and high concentration N-type semiconductor layer having an n-type impurity concentration of 5×10¹⁸ cm⁻³ to 5×10²⁰ cm⁻³ in this order, the N-type semiconductor layer is in contact with the N electrode, and the semiconductor multi-layer film has a convex.

Claims

1. A group III nitride semiconductor light emitting device comprising (a1), (b1) and (c1) in this order:

(a1) an N electrode,

(b1) a semiconductor multi-layer film,

(c1) a transparent electric conductive oxide P electrode,

wherein the semiconductor multi-layer film comprises an N-type semiconductor layer, light emitting layer, P-type semiconductor layer and high concentration N-type semiconductor layer having an n-type impurity concentration of 5×

10¹⁸ cm<sup>−

3</sup> to 5×

10²⁰ cm<sup>−

3</sup> in this order, the N-type semiconductor layer is in contact with the N electrode, and the semiconductor multi-layer film has a convex.

2. The device according to claim 1, wherein there are at least two convexes and the shapes and sizes thereof are identical.

3. The device according to claim 1, wherein the convexes show an arrangement of non-periodic configuration.

4. The device according to claim 1, wherein in the convex, a cross-section parallel to the semiconductor multi-layer film is circular, a cross-section vertical to the semiconductor multi-layer film contains a curved line and the curvature radius thereof increases monotonously from the apex toward peripheral parts.

5. The device according to claim 1, wherein the convex has an area density of 2×

10⁶ cm<sup>−

2</sup> to 2×

10¹⁰ cm<sup>−

2</sup>.

6. The device according to claim 1, wherein the proportion of the surface areas of the convexes occupying with respect to the total surface area of the device is not less than 2.3%.

7. The device according to claim 2, wherein a plane obtained by connecting the apexes of the convexes and an interface between the transparent electric conductive oxide P electrode and the semiconductor multi-layer film are in the same plane.

8. The device according to claim 1, situated above the convexes and N-type semiconductor layer.

9. The device according to claim 1, wherein the semiconductor multi-layer film has a total thickness of 20 μ

m to 80 μ

m.

10. A method for producing a surface light emitting type semiconductor light emitting device comprising the steps (I-1) to (I-4):

step (I-1);

an N-type semiconductor layer, light emitting layer, P-type semiconductor layer and high concentration N-type semiconductor layer having an n-type impurity concentration of 5×

10¹⁸ cm<sup>−

3</sup> to 5×

10²⁰ cm<sup>−

3</sup> are allowed to grow on a substrate to obtain a semiconductor multi-layer film,

step (I-2);

particles having an average particle size of 0.01 μ

m to 10 μ

m are placed at an area density of 2×

10⁶ cm<sup>−

2</sup> to 2×

10¹⁰ cm<sup>−

2</sup> on the high concentration N-type semiconductor layer of the semiconductor multi-layer film,

step (I-3);

the semiconductor multi-layer film is dry-etched using the particles as an etching mask, to form a convex,

step (I-4);

a P electrode is formed on the semiconductor multi-layer film.

11. The method according to claim 10, wherein the particles used in the step (I-2) are made of an inorganic material.

12. The method according to claim 11, wherein the inorganic material is selected from the group consisting of oxides, nitrides, carbides, borides, sulfides, selenides and metals.

13. The method according to claim 12, wherein the inorganic material is an oxide.

14. The method according to claim 13, wherein the oxide is silica.

15. A group III nitride semiconductor light emitting device comprising (a2), (b2) and (c2):

(a2) a transparent electric conductive oxide N electrode,

(b2) a semiconductor multi-layer film,

(c2) a P electrode,

wherein the semiconductor multi-layer film comprises a high concentration N-type semiconductor layer having an n-type impurity concentration of 5×

10¹⁸ cm<sup>−

3</sup> to 5×

10²⁰ cm<sup>−

3</sup>, N-type semiconductor layer, light emitting layer and P-type semiconductor layer in this order, the P-type semiconductor layer is in contact with the P electrode, and the semiconductor multi-layer film has a convex.

16. The device according to claim 15, wherein there are at least two convexes and the shapes and sizes thereof are identical.

17. The device according to claim 15, wherein the convexes show an arrangement of non-periodic configuration.

18. The device according to claim 15, wherein in the convex, a cross-section parallel to the semiconductor multi-layer film is circular, a cross-section vertical to the semiconductor multi-layer film contains a curved line and the curvature radius thereof increases monotonously from the apex toward peripheral parts.

19. The device according to claim 15, wherein the convex has an area density of 2×

10⁶ cm<sup>−

2</sup> to 2×

10¹⁰ cm<sup>−

2</sup>.

20. The device according to claim 15, wherein the proportion of the surface areas of the convexes occupying with respect to the total surface area of the device is not less than 2.3%.

21. The device according to claim 15, wherein a plane obtained by connecting the apexes of the convexes and an interface between the transparent electric conductive oxide N electrode and the semiconductor multi-layer film are in the same plane.

22. The device according to claim 15, situated above the convexes and P-type semiconductor layer.

23. The device according to claim 15, wherein the semiconductor multi-layer film has a total thickness of 20 μ

m to 80 μ

m.

24. A method for producing a group III nitride semiconductor light emitting device comprising the steps (II-1) to (II-7):

step (II-1);

a high concentration N-type semiconductor layer having an n-type impurity concentration of 5×

10¹⁸ cm<sup>−

3</sup> to 5×

10²⁰ cm³, N-type semiconductor layer, light emitting layer and P-type semiconductor layer are allowed to grow in this order on a substrate to obtain a semiconductor multi-layer film,

step (II-2);

a P electrode is formed on the semiconductor multi-layer film,

step (II-3);

a support is joined to the P electrode,

step (II-4);

the substrate is separated from the semiconductor multi-layer film,

step (II-5);

particles having an average particle size of 0.01 μ

m to 10 μ

m are placed at an area density of 2×

10⁶ cm<sup>−

2</sup> to 2×

10¹⁰ cm² on the high concentration N-type semiconductor layer of the semiconductor multi-layer film,

step (II-6);

the semiconductor multi-layer film is dry-etched using the particles as an etching mask, to form a convex,

step (II-7);

an N electrode is formed on the high concentration N-type semiconductor layer.

25. The method according to claim 24, wherein the particles used in the step (II-5) are made of an inorganic material.

26. The method according to claim 25, wherein the inorganic material is selected from the group consisting of oxides, nitrides, carbides, borides, sulfides, selenides and metals.

27. The method according to claim 26, wherein the inorganic material is an oxide.

28. The method according to claim 27, wherein the oxide is silica.