NITRIDE SEMICONDUCTOR CRYSTAL WITH SURFACE TEXTURE

• US 20080073657A1
• Filed: 08/23/2007
• Published: 03/27/2008
• Est. Priority Date: 08/28/2006
• Status: Active Grant

• Current Assignee: Stanley Electric Company Limited
• Original Assignee: Stanley Electric Company Limited
• Inventors: Liang, Ji-Hao, Kajikawa, Masataka, Tsuchiya, Masahiko, Chinone, Takako
• Granted Patent: US 8,158,993 B2
• Time in Patent Office: Days
• US Class Current: 257/89
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

A nitride semiconductor light emitting device is formed by: forming a resist pattern on a first nitride semiconductor layer formed on a substrate, the resist pattern having a region whose inclination angle relative to a substrate surface changes smoothly as viewed in a cross section perpendicular to the substrate surface; etching the substrate by using the resist pattern as a mask to transfer the resist pattern to the first nitride semiconductor layer; and forming an light emitting layer on the patterned first nitride semiconductor layer. The nitride semiconductor light emitting device can emit near-white light or have a wavelength range generally equivalent to or near visible light range.

Claims

1. A method for manufacturing a nitride semiconductor light emitting device, comprising the steps of:

(a) forming a resist pattern on a first nitride semiconductor layer formed above a substrate, said resist pattern having a region whose inclination angle of an upper surface relative to a substrate surface changes smoothly as viewed in a cross section perpendicular to the substrate surface;

(b) etching said substrate by using said resist pattern as a mask to transfer said resist pattern to said first nitride semiconductor layer; and

(c) forming an active layer on said patterned first nitride semiconductor layer.

2. The method for manufacturing a nitride semiconductor light emitting device according to claim 1, wherein said step (a) comprises:

(a-1) coating a resist layer on said first nitride semiconductor layer; and

(a-2) exposing and developing said resist layer to form said resist pattern having said region.

3. The method for manufacturing a nitride semiconductor light emitting device according to claim 2, wherein said active layer includes an n-type nitride semiconductor layer, a p-type nitride semiconductor layer and a plurality of light emitting regions having different light emission wavelength ranges.

4. The method for manufacturing a nitride semiconductor light emitting device according to claim 3, wherein said inclination angle is 0°

to 30°

along an a-axis direction or 0°

to 90°

along an M-axis direction.

5. The method for manufacturing a nitride semiconductor light emitting device according to claim 4, wherein said resist pattern has a plurality of projections.

6. The method for manufacturing a nitride semiconductor light emitting device according to claim 5, wherein said projections are disposed in hexagonal close-packed configuration.

7. The method for manufacturing a nitride semiconductor light emitting device according to claim 5, wherein said projections are rib-like stripes.

8. A method for manufacturing a nitride semiconductor crystal, comprising the steps of:

(a) forming a resist pattern on a first nitride semiconductor layer formed above a substrate, said resist pattern having a region whose inclination angle of an upper surface relative to a substrate surface changes smoothly as viewed in a cross section perpendicular to the substrate surface;

(b) etching said substrate by using said resist pattern as a mask to transfer said resist pattern to said first nitride semiconductor layer; and

(c) forming an active layer on said patterned first nitride semiconductor layer.

9. The method for manufacturing a nitride semiconductor crystal according to claim 8, wherein said step (a) comprises:

(a-1) coating a resist layer on said first nitride semiconductor layer; and

(a-2) exposing and developing said resist to form said resist pattern having said region.

10. The method for manufacturing a nitride semiconductor crystal according to claim 9, wherein said active layer includes an n-type nitride semiconductor layer, a p-type nitride semiconductor layer and a plurality of light emitting regions having different light emission wavelength ranges.

11. A nitride semiconductor light emitting device comprising:

a substrate; and

an active layer stacked above said substrate and having a surface including a region whose inclination angle relative to a substrate surface changes smoothly as viewed in a cross section perpendicular to the substrate surface.

12. The nitride semiconductor light emitting device according to claim 11, wherein said active layer includes an n-type nitride semiconductor layer and a p-type nitride semiconductor layer, and a plurality of light emitting regions having different light emission wavelength ranges.

13. The nitride semiconductor light emitting device according to claim 12, wherein material of said active layer contains nitride semiconductor represented by a composition formula of Al_xIn_yGa_(1-x-y)N.

14. The nitride semiconductor light emitting device according to claim 13, wherein said inclination angle is 0°

to 30°

along an a-axis direction or 0°

to 90°

along an M-axis direction.

15. The nitride semiconductor light emitting device according to claim 14, wherein said surface has a plurality of projections.

16. The nitride semiconductor light emitting device according to claim 15, wherein said projections are disposed in hexagonal close-packed configuration.

17. The nitride semiconductor light emitting device according to claim 15, wherein said projections are rib-like stripes.

18. A nitride semiconductor crystal comprising:

a substrate; and

an active layer stacked above said substrate and having a surface including a region whose inclination angle relative to a substrate surface changes smoothly as viewed in a cross section perpendicular to the substrate surface.

19. The nitride semiconductor crystal according to claim 18, wherein said active layer includes an n-type nitride semiconductor layer and a p-type nitride semiconductor layer, and a plurality of light emitting regions having different light emission wavelength ranges.

20. The nitride semiconductor crystal according to claim 19, wherein said inclination angle is 0°

to 30°

along an a-axis direction or 0°

to 90°

along an M-axis direction.