Light emitting element having an irregular surface, light emitting device using the light emitting element, and method for manufacturing light emitting element

• US 7,989,836 B2
• Filed: 02/03/2010
• Issued: 08/02/2011
• Est. Priority Date: 04/04/2006
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Uemura, Toshiya
• Primary Examiner(s): Soward; Ida M
• Application Number:
  US12/656,558
• Publication Number:
  US 20100140650A1
• Time in Patent Office: 545 Days
• Field of Search: 257 98-100, 257/E33.056, 257/E33.058, 257/E33.059, 257/E33.061, 257/E33.068, 257/E33.073, 257/E33.074, 257/95, 257/433, 257/434, 438/26, 438/116
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2924/01004 Beryllium [Be]
• CPC Class Codes: H01L 2924/01012 Magnesium [Mg]
• CPC Class Codes: H01L 2924/0102 Calcium [Ca]
• CPC Class Codes: H01L 2924/01025 Manganese [Mn]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• 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 33/52 Encapsulations

Abstract

A light emitting device includes a light emitting element, including a substrate including group III nitride compound semiconductor, a luminous layer structure including group III nitride compound semiconductor, the luminous layer structure formed on a first surface of the substrate, and an irregular surface formed on a second surface of the substrate, the second surface including a principal light emission surface, and a translucent sealing member for sealing the light emitting element, the translucent sealing member being separated from the second surface. At least one of translucent gel material and an inert gas is filled between the light emitting element and the translucent sealing member.

Claims

1. A light emitting device, comprising:

a light emitting element, comprising;

a substrate comprising group III nitride compound semiconductor;

a luminous layer structure comprising group III nitride compound semiconductor, said luminous layer structure formed on a first surface of said substrate; and

an irregular surface formed on a second surface of said substrate, said second surface comprising a principal light emission surface; and

a translucent sealing member for sealing said light emitting element, said translucent sealing member being separated from said second surface,

wherein at least one of translucent gel material and an inert gas is filled between said light emitting element and said translucent sealing member.

2. The light emitting device according to claim 1, wherein said translucent gel material comprises at least one of a silicon gel, a polyimide, and a fluoride gel.

3. The light emitting device according to claim 2, wherein the gel material comprises fluorine gel.

4. The light emitting device according to claim 3, wherein the inert gas comprises at least one of nitrogen gas and rare gas.

5. The light emitting device according to claim 1, wherein said translucent sealing member comprises a resin.

6. The light emitting device according to claim 5, wherein the resin comprises an epoxy resin.

7. The light emitting device according to claim 5, wherein phosphor grains are dispersed in said resin.

8. The light emitting device according to claim 1, wherein the light emitting element is mounted on a base substrate, and wherein a reflecting member is formed on the base substrate surrounding the light emitting element.

9. The light emitting device according to claim 1, wherein an inner surface of the translucent sealing member is formed in a spherical surface.

10. The light emitting device according to claim 1, wherein an outer surface of the translucent sealing member is formed in a spherical surface.

11. The light emitting device according to claim 1, wherein the translucent gel material comprises a different material than that of the translucent sealing member.

12. The light emitting device according to claim 1, wherein the at least one of the translucent gel material and the inert gas is filled in a space portion located between the light emitting element and the translucent sealing member.

13. The light emitting device according to claim 1, further comprising a space portion between the light emitting element and the translucent sealing member, wherein the space portion is filled with the at least one of the translucent gel material and the inert gas.

14. The light emitting device according to claim 13, wherein the space portion creates a buffer between the light emitting element and the translucent sealing member.

15. The light emitting device according to claim 1, wherein the translucent gel material has a smaller hardness than the translucent sealing member.

16. The light emitting device, comprising:

a light emitting element, comprising;

a substrate;

a luminous layer structure formed on a first surface of the substrate; and

an irregular surface formed on a second surface of the substrate, the second surface comprising a principal light emission surface;

a translucent sealing member for sealing the light emitting element; and

a space portion located between the light emitting element and the translucent sealing member,

wherein the space portion is filled with at least one of a translucent gel material that comprises a material different than that of the translucent sealing member, and an inert gas.

17. The light emitting device according to claim 16, wherein, if an incident angle of a light is 45 degrees or more on an interface between the space portion and the sealing member, the light is repeatedly reflected within the sealing member to arrive at the interface.

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

forming a light emitting element, comprising;

forming a substrate;

forming a luminous layer structure on a first surface of the substrate; and

forming an irregular surface on a second surface of the substrate;

forming a translucent sealing member; and

forming a space portion between the light emitting element and the translucent sealing member,

wherein the space portion is filled with at least one of a translucent gel material that comprises a material different than that of the translucent sealing member, and an inert gas.

19. The method according to claim 18, wherein said forming the luminous layer comprises:

growing a group III nitride compound semiconductor on a sapphire substrate;

separating the sapphire substrate from the group III nitride compound semiconductor by a laser lift-off method;

soaking the group III nitride compound semiconductor in a KOH aqueous solution; and

applying ultraviolet light on a surface of the group III nitride compound semiconductor for about one minute.

20. The method according to claim 18, wherein said forming the irregular surface comprises:

heating the second surface of the substrate while soaking the second surface of the substrate in a KOH aqueous solution for about ten minutes.