Group III nitride compound semiconductor light-emitting element

• US 7,157,294 B2
• Filed: 06/05/2002
• Issued: 01/02/2007
• Est. Priority Date: 06/06/2001
• Status: Expired due to Fees

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Uemura, Toshiya, Hashimura, Masaki
• Primary Examiner(s): JACKSON JR, JEROME
• Application Number:
  US10/162,255
• Publication Number:
  US 20020197764A1
• Time in Patent Office: 1,672 Days
• Field of Search: 438/27, 438/47, 257/98
• US Class Current: 438/27
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

In a flip chip type Group III nitride compound semiconductor light-emitting element, a surface of a substrate serving as a light-emitting surface is formed as a rough surface so that radiated light is scattered by the surface.

Claims

1. A method of forming a Group III nitride compound semiconductor light-emitting element said method comprising:

forming a buffer layer on a sapphire substrate;

forming a Group III nitride compound semiconductor on said buffer layer; and

after said forming said Group III Nitride compound semiconductor, preparing a light-emitting surface of said substrate which is opposite said buffer layer by grinding said surface using an abrasive material having a particle size in a range of 10 μ

m≦

r≦

50 μ

m until said substrate has a predetermined thickness and said surface has a roughness in a range of 0.05≦

Ra≦

1 μ

m for uniformizing light emitted from said light-emitting surface.

2. A method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said preparing said surface comprises roughening said surface such that light emitted from said surface is uniformly distributed.

9. A method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said light-emitting surface is formed on a side of said substrate which is opposite said Group III nitride compound semiconductor.

10. A method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said light-emitting surface comprises randomly distributed irregularities.

12. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said predetermined thickness of said substrate comprises 100 μ

m.

13. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said roughness of said light-emitting surface causes a scattering of light which is incident on said surface to provide a uniform light emission from said light-emitting surface.

14. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said roughness of said surface suppresses an influence of a variation in thickness of said Group III nitride compound semiconductor on a characteristic of light emitted from said light-emitting element.

15. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, further comprising:

after said preparing said substrate, separating said substrate into chips,

wherein said separating said substrate into chips is performed after said preparing said substrate without performing a substrate thickness reducing step therebetween.

16. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said preparing said substrate simultaneously prepares said surface to have a desired roughness and reduces a thickness of said substrate to said predetermined thickness.

18. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said light-emitting surface comprises a surface a of said sapphire substrate.

19. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said Group III nitride compound semiconductor comprises a plurality of Group III nitride compound semiconductor layers which includes a light-emitting layer, and

wherein light from said light-emitting layer is emitted from said light-emitting surface via said plurality of Group III nitride compound semiconductor layers.

20. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said light-emitting element comprises a flip-chip light-emitting element, and said light-emitting surface of said sapphire substrate comprises a surface of said substrate from which light exits said flip-chip light-emitting element.

21. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 20, wherein said light-emitting surface comprises a surface of said substrate at an interface between said substrate and a sealing resin formed on said flip-chip light-emitting element.

22. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said buffer layer improves a crystallinity of said Group III nitride compound semiconductor formed on said buffer layer.

23. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said forming said Group III nitride compound semiconductor comprises using metal organic chemical vapor deposition (MOCVD).

24. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said buffer layer comprises a Group III nitride compound semiconductor.

25. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said buffer layer comprises one of AlN, InN, GaN, AlGaN, InGaN, and AlInGaN.

26. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said forming said buffer layer comprises using one of molecular beam epitaxy (MBE), halide vapor phase epitaxy (HVPE), sputtering, ion-plating, and an electron shower.

27. A method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said preparing said surface is performed after said forming said buffer layer.

28. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 1, wherein said roughness of said surface suppresses an influence of a variation in thickness of said buffer layer on a characteristic of light emitted from said light-emitting element.

3. A method of forming a Group III nitride compound semiconductor light-emitting element, said method comprising:

forming a buffer layer on a sapphire substrate;

forming a Group III nitride compound semiconductor on said buffer layer;

forming at least one electrode on a same said side of said substrate as said Group III nitride compound semiconductor; and

after said forming said Group III Nitride compound semiconductor, preparing a light-emitting surface on a side of said substrate which is opposite said buffer layer by grinding said surface using an abrasive material having a particle size in a range of 10 μ

m ≦

r≦

50 μ

m until said substrate has a predetermined thickness and said light-emitting surface has a roughness in a range of 0.05 ≦

Ra≦

1 μ

m uniformizing light emitted from said light-emitting surface.

4. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 3, wherein said preparing said light-emitting surface comprises roughening said surface so that light emitted from said surface is uniformly distributed.

5. The method of forming a Group III nitride compound semiconductor light-emitting element according to claim 3,

wherein said preparing said light-emitting surface comprises forming grooves at intervals of a desired pitch in said light-emitting surface.

6. A method of forming a Group III nitride compound semiconductor light-emitting element according to claim 3, wherein said preparing said substrate is performed before said forming said Group III nitride compound semiconductor on said substrate.

7. A method of forming a Group III nitride compound semiconductor light-emitting element according to claim 6, wherein said Group III nitride compound semiconductor is grown on a non-abraded surface of said substrate.

8. A method of forming a Group III nitride compound semiconductor light-emitting element according to claim 3, wherein said preparing said substrate is performed after said forming said at least one electrode.

11. The Group III nitride compound semiconductor light-emitting element according to claim 3, wherein said at least one electrode comprises a positive electrode and a negative electrode.

17. A method of forming a light-emitting device, comprising:

forming a light-emitting element comprising;

forming a buffer layer on a sapphire substrate;

forming a Group III nitride compound semiconductor on said buffer layer; and

after said forming said Group III Nitride compound semiconductor, preparing a light-emitting surface of said substrate which is opposite said buffer layer by grinding said surface using an abrasive material having a particle size in a range of 10 μ

m≦

r≦

50 μ

m until said substrate has a predetermined thickness and said surface has a roughness in a range of 0.05≦

Ra≦

1 μ

m for uniformizing light emitted from said light-emitting surface; and

forming a support on which said light-emitting element is mounted.