Group III nitride semiconductor light emitting device and method for producing the same

• US 8,097,891 B2
• Filed: 02/13/2007
• Issued: 01/17/2012
• 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
• Primary Examiner(s): Richards, N Drew
• Assistant Examiner(s): Singal, Ankush K
• Application Number:
  US12/223,986
• Publication Number:
  US 20100155754A1
• Time in Patent Office: 1,799 Days
• Field of Search: 438/29, 438/46, 438/45, 438/433, 257/98, 257/E33.067, 257/E21.211, 257/99, 257/103, 257/E33.064, 257/E33.025, 257/E33.066, 257/E33.045
• 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 at least two convex shapes and the shapes and sizes thereof are identical, and

wherein a plane obtained by connecting the apexes of the convex shapes and an interface between the transparent electric conductive oxide P electrode and the semiconductor multi-layer film are in the same plane.

2. 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 shape,

step (I-4);

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

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

4. The method according to claim 3, wherein the inorganic material is selected from the group consisting of oxides, nitrides, carbides, borides, sulfides, selenides and metals.

5. The method according to claim 4, wherein the inorganic material is an oxide.

6. The method according to claim 5, wherein the oxide is silica.

7. 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 multilayer film has a convex shape.

8. The device according to claim 7, wherein there are at least two convex shapes and the shapes and sizes thereof are identical.

9. The device according to claim 7, wherein the convex shapes show an arrangement of non-periodic configuration.

10. The device according to claim 7, wherein in the convex shape, 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.

11. The device according to claim 7, wherein the convex shape has an area density of 2×

10⁶ cm<sup>−

2</sup> to 2×

10¹⁰ cm<sup>−

2</sup>.

12. The device according to claim 7, wherein the proportion of the surface areas of the convex shapes occupying with respect to the total surface area of the device is not less than 2.3%.

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

14. The device according to claim 7, wherein the convex shapes are situated above the P-type semiconductor layer.

15. The device according to claim 7, wherein the semiconductor multi-layer film has a total thickness of 20 μ

m to 80 μ

m.

16. 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 cm<sup>−

3</sup>, 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 cm<sup>−

2</sup> 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 shape,

step (II-7);

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

17. The method according to claim 16, wherein the particles used in the step (II-5) are made of an inorganic material.

18. The method according to claim 17, wherein the inorganic material is selected from the group consisting of oxides, nitrides, carbides, borides, sulfides, selenides and metals.

19. The method according to claim 18, wherein the inorganic material is an oxide.

20. The method according to claim 19, wherein the oxide is silica.