Semiconductor light emitting element having three side surfaces inclined to connect the top and bottom surfaces of the transparent substrate

• US 7,329,903 B2
• Filed: 03/08/2006
• Issued: 02/12/2008
• Est. Priority Date: 03/14/2002
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kondo, Katsufumi, Nitta, Koichi, Endo, Yoshiki, Akaike, Yasuhiko, Konno, Kuniaki, Nakamura, Takafumi
• Primary Examiner(s): Mai; Anh D
• Application Number:
  US11/371,873
• Publication Number:
  US 20060145171A1
• Time in Patent Office: 706 Days
• Field of Search: 257/95, 257/98
• US Class Current: 257/95
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• 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 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• 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 2924/10155 being other than a cuboid
• CPC Class Codes: H01L 2924/10158 at the passive surface
• 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 33/38 with a particular shape

Abstract

For the purpose of enhancing the light extracting efficiency, improving the production yield and elongating the lifetime of a semiconductor light emitting element or a semiconductor light emitting device using the element, a semiconductor light emitting element comprises: a light emitting layer that emits light; and a substrate transparent to the light emitted from the light emitting layer. The substrate defines a top surface supporting the light emitting layer thereon; a bottom surface opposed to the top surface and side surfaces connecting the top surface and the bottom surface. Each of the side surfaces is composed of first side surface extending from the top surface toward the bottom surface, second side surface extending from the first side surface toward the bottom surface, and third side surface extending from the second side surface toward the bottom surface. The third side surfaces incline to diverge toward the top surface, and the second side surfaces incline to diverge more toward the top surface to extract part of the light from the light emitting layer externally. The first side surfaces are formed by cleavage along cleavable planes.

Claims

1. A semiconductor light emitting element comprising:

a light emitting layer for emitting light; and

a substrate transparent to the light emitted from the light emitting layer, and having;

a top surface on which the light emitting layer is formed;

a bottom surface opposed to the top surface; and

side surfaces connecting the top surface and the bottom surface,

wherein each of the side surfaces is composed of first side surface extending from the top surface toward the bottom surface, second side surface extending from the first side surface toward the bottom surface, and third side surface extending from the second side surface toward the bottom surface,

wherein the third side surfaces incline to diverge toward the top surface, and the second side surfaces incline to diverge more toward the top surface to extract part of the light from the light emitting layer externally, and

wherein the first side surfaces incline to converge toward the top surface from the direction vertical to the top surface by an angle equal to or larger than 16° and

equal to or smaller than 60°

.

2. The semiconductor light emitting element according to claim 1 wherein the substrate is made of GaP.

3. The semiconductor light emitting element according to claim 1 wherein the light emitting layer includes InGaAlP layer.

4. The semiconductor light emitting element according to claim 1 wherein the angle of inclination of the second side surfaces of the substrate relative to the direction vertical to the top surface is equal to or larger than 20°

and equal to or smaller than 40°

.

5. The semiconductor light emitting element according to claim 2 wherein the second side surfaces and the third side surfaces define a plurality of depressions and protrusions having a height equal to or higher than 1 μ

m and equal to or lower than 2 μ

m.

6. The semiconductor light emitting element comprising:

a light emitting layer for emitting light; and

a substrate transparent to the light emitted from the light emitting layer, and having;

a top surface on which the light emitting layer is formed;

a bottom surface opposed to the top surface; and

side surfaces connecting the top surface and the bottom surface,

wherein each of the side surfaces is composed of first side surface extending from the top surface toward the bottom surface, second side surface extending from the first side surface toward the bottom surface, and third side surface extending from the second side surface toward the bottom surface,

wherein the third side surfaces incline to diverge toward the top surface, and the second side surfaces incline to diverge more toward the top surface to extract part of the light from the light emitting layer externally,

wherein the first side surfaces incline to converge toward the top surface from the direction vertical to the top surface by an angle equal to or larger than 16° and

equal to or smaller than 60°

, and

wherein grooves are formed in the bottom surface of the substrate.

7. The semiconductor light emitting element according to claim 6 wherein the second side surfaces define a plurality of depressions and protrusions having a height equal to or higher than 1 μ

m and equal to or lower than 2 μ

m.

8. The semiconductor Light emitting element according to claim 6 wherein the second side surfaces and the third side surfaces define a plurality of depressions and protrusions having a height equal to or higher than 1 μ

m and equal to or lower than 2 μ

m.

9. The semiconductor light emitting element according to claim 7 wherein the substrate is made of GaP.

10. The semiconductor light emitting element according to claim 7 wherein the light emitting layer includes InGaAlP layer.

11. The semiconductor light emitting element according to claim 7 wherein the angle of inclination of the second side surfaces of the substrate relative to the direction vertical to the top surface is equal to or larger than 20°

and equal to or smaller than 40°

.

12. The semiconductor light emitting element according to claim 8 wherein the substrate is made of GaP.

13. The semiconductor light emitting element according to claim 8 wherein the light emitting layer includes InGaAlP layer.

14. The semiconductor light emitting element according to claim 8 wherein the angle of inclination of the second side surfaces of the substrate relative to the direction vertical to the top surface is equal to or larger than 20°

and equal to or smaller than 40°

.

15. The semiconductor light emitting element according to claim 6 wherein an electrode is formed on a first area of the bottom surface of the substrate other than a second area where the grooves are formed.

16. The semiconductor light emitting element according to claim 7 wherein an electrode is formed on a first area of the bottom surface of the substrate other than a second area where the grooves are formed.

17. The semiconductor light emitting device, comprising:

a lead frame; and

a semiconductor light emitting element mounted on the lead frame, said semiconductor light emitting element comprising;

a light emitting layer for emitting light; and

a substrate transparent to the light emitted from the light emitting layer, and having;

a top surface on which the light emitting layer is formed;

a bottom surface opposed to the top surface; and

side surfaces connecting the top surface and the bottom surface,

wherein each of the side surfaces is composed of a first side surface extending from the top surface toward the bottom surface, a second side surface extending from the first side surface toward the bottom surface, and a third side surface extending from the second side surface toward the bottom surface,

wherein the third side surfaces incline to diverge toward the top surface, and the second side surfaces incline to diverge more toward the top surface to extract part of the light from the light emitting layer externally,

wherein the first side surfaces incline to converge toward the top surface from the direction vertical to the top surface by an angle equal to or larger than 16° and

equal to or smaller than 60°

, and

wherein grooves are formed in the bottom surface of the substrate.

18. The semiconductor light emitting device according to claim 17 wherein an electrode is formed on a first area of the bottom surface of the substrate other than a second area thereof where the grooves are formed.

19. The semiconductor light emitting device according to claim 17 wherein the second side surfaces define a plurality of depressions and protrusions.

20. The semiconductor light emitting device according to claim 17 wherein the second side surfaces and the third side surfaces define a plurality of depressions and protrusions.

21. The semiconductor light emitting device according to claim 17 wherein said lead frame comprises a first lead frame portion to be connected to one of power supply voltages and a second lead frame portion to be connected to the other of the power supply voltages, said semiconductor light emitting element further comprises a first and second electrodes, the first electrode being formed on the bottom surface of the substrate and the second electrode being formed on the light emitting layer, the first electrode is connected to the first lead frame portion of the lead frame and the second electrode is connected to the second lead frame portion of the lead frame via an Au wire.