Semiconductor light emitting element and semiconductor light emitting device

• US 20030197191A1
• Filed: 03/13/2003
• Published: 10/23/2003
• Est. Priority Date: 03/14/2002
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Akaike, Yasuhiko, Konno, Kuniaki, Kondo, Katsufumi, Nitta, Koichi, Nakamura, Takafumi, Endo, Yoshiki
• Granted Patent: US 7,038,245 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• 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 surface incline to diverge toward the top surface, and the second side surface 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 are cleavable planes.

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

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

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

and equal to or smaller than 40°

.

5. A semiconductor light emitting element according to claim 2 wherein the substrate is off-axis (100) GaP substrate and the off-axis angle of the substrate is equal to or larger than 5°

and equal to or smaller than 30°

.

6. A semiconductor light emitting element according to claim 2 wherein the second side surfaces and the third side surfaces have 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.

7. A semiconductor light emitting element according to claim 1 wherein grooves are formed in the bottom surface of the substrate.

8. 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°

.

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

10. A semiconductor light emitting element according to claim 8 wherein the light emitting layer includes InGaAlP layer.

11. A 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°

.

12. A semiconductor light emitting element according to claim 9 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.

13. A semiconductor light emitting device comprising:

a semiconductor light emitting element including;

a light emitting layer for emitting light; and

a substrate transparent to the light 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 surface 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 are cleavable planes;

a lead frame; and

a mounting agent which is electrically conductive and mounts the bottom surface of the substrate of the semiconductor light emitting element to the lead frame.

14. A semiconductor light emitting device according to claim 13 wherein the substrate of the semiconductor light emitting element is made of GaP, and 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.

15. A semiconductor light emitting device according to claim 14 wherein grooves are formed in the bottom surface of the substrate.

16. A semiconductor light emitting device comprising:

a semiconductor light emitting element including;

a light emitting layer for emitting light; and

a substrate transparent to the light 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°

;

a lead frame; and

a mounting agent which is electrically conductive and mounts the bottom surface of the substrate of the semiconductor light emitting element to the lead frame.

17. A semiconductor light emitting device according to claim 16 wherein the substrate of the semiconductor light emitting element is made of GaP, and 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.

18. A semiconductor light emitting device according to claim 17 wherein grooves are formed in the bottom surface of the substrate.