Nitride-based semiconductor light-emitting device

• US 20050199891A1
• Filed: 02/18/2005
• Published: 09/15/2005
• Est. Priority Date: 03/10/2004
• Status: Active Grant

• Current Assignee: LEDVANCE GmbH (MLS Co. Ltd.)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Kunisato, Tatsuya, Oota, Kiyoshi, Hiroyama, Ryoji, Hata, Masayuki
• Granted Patent: US 7,154,123 B2
• Time in Patent Office: Days
• US Class Current: 257/85
• 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 33/20 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 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating

Abstract

A nitride-based semiconductor light-emitting device capable of improving light extraction efficiency is provided. This nitride-based semiconductor light-emitting device comprises a first nitride-based semiconductor layer formed on the surface of a conductive substrate, an active layer formed on the first nitride-based semiconductor layer, a second nitride-based semiconductor layer formed on the active layer and a light transmission layer, formed on the second nitride-based semiconductor layer, having a carrier concentration lower than the carrier concentration of the second nitride-based semiconductor layer.

Claims

1. A nitride-based semiconductor light-emitting device comprising:

a first conductive type first nitride-based semiconductor layer formed on the surface of a conductive substrate;

an active layer of a nitride-based semiconductor formed on said first nitride-based semiconductor layer;

a second conductive type second nitride-based semiconductor layer formed on said active layer; and

a light transmission layer, formed on said second nitride-based semiconductor layer, consisting of a nitride-based semiconductor layer having a carrier concentration lower than the carrier concentration of said second nitride-based semiconductor layer.

2. The nitride-based semiconductor light-emitting device according to claim 1, wherein

said first conductive type first nitride-based semiconductor layer is a p-type nitride-based semiconductor layer, and

said second conductive type second nitride-based semiconductor layer is an n-type nitride-based semiconductor layer.

3. The nitride-based semiconductor light-emitting device according to claim 1, wherein

said light transmission layer includes an undoped nitride-based semiconductor layer.

4. The nitride-based semiconductor light-emitting device according to claim 1, wherein

said light transmission layer includes a second conductive type nitride-based semiconductor layer doped with a second conductive type impurity.

5. The nitride-based semiconductor light-emitting device according to claim 1, wherein

said light transmission layer includes a nitride-based semiconductor layer containing at least Al.

6. The nitride-based semiconductor light-emitting device according to claim 5, wherein

said light transmission layer includes said nitride-based semiconductor layer of AlGaN.

7. The nitride-based semiconductor light-emitting device according to claim 1, wherein

said light transmission layer has a textured surface.

8. The nitride-based semiconductor light-emitting device according to claim 1, further comprising a layer, formed on said light transmission layer, having a textured surface and consisting of a material other than a nitride-based semiconductor.

9. The nitride-based semiconductor light-emitting device according to claim 8, wherein

said layer consisting of said material other than a nitride-based semiconductor includes an insulating film.

10. The nitride-based semiconductor light-emitting device according to claim 1, wherein

said light transmission layer consists of a material substantially identical to the material for said second nitride-based semiconductor layer.

11. The nitride-based semiconductor light-emitting device according to claim 10, wherein

said light transmission layer and said second nitride-based semiconductor layer are formed by GaN layers.

12. The nitride-based semiconductor light-emitting device according to claim 10, wherein

said light transmission layer and said second nitride-based semiconductor layer are formed by AlGaN layers.

13. The nitride-based semiconductor light-emitting device according to claim 1, wherein

said first nitride-based semiconductor layer is formed on the surface of said conductive substrate through a first electrode layer, and

said first electrode layer also functions as a reflecting film.

14. The nitride-based semiconductor light-emitting device according to claim 13, wherein

the surface of said first electrode layer closer to said first nitride-based semiconductor layer is textured.

15. The nitride-based semiconductor light-emitting device according to claim 1, wherein

said light transmission layer is formed on a partial region of said second nitride-based semiconductor layer,

the nitride-based semiconductor light-emitting device further comprising a second electrode layer formed to be in contact with a region of the surface of said second nitride-based semiconductor layer not formed with said light transmission layer.

16. The nitride-based semiconductor light-emitting device according to claim 15, wherein

said light transmission layer has an opening, and

said second electrode layer is formed in said opening to be in contact with the surface of said second nitride-based semiconductor layer.

17. The nitride-based semiconductor light-emitting device according to claim 15, further comprising a layer, formed on said light transmission layer, consisting of a material other than a nitride-based semiconductor, wherein

said layer consisting of said material other than a nitride-based semiconductor and said light transmission layer have openings, and

said second electrode layer is formed in said openings to be in contact with the surface of said second nitride-based semiconductor layer.

18. The nitride-based semiconductor light-emitting device according to claim 1, further comprising a protective film covering the side surfaces of said first nitride-based semiconductor layer, said active layer, said second nitride-based semiconductor layer and said light transmission layer.

19. The nitride-based semiconductor light-emitting device according to claim 1, wherein

said light transmission layer has a side surface inclined by a prescribed angle with respect to the normal of a light emission surface.

20. The nitride-based semiconductor light-emitting device according to claim 1, wherein

light formed in said active layer is emitted through said light transmission layer.