Semiconductor light-emitting element

• US 8,552,447 B2
• Filed: 02/16/2011
• Issued: 10/08/2013
• Est. Priority Date: 02/17/2010
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Yahata, Kosuke, Deguchi, Masashi, Mizobuchi, Takashi, Mori, Takahiro, Totani, Shingo
• Primary Examiner(s): Lee, Eugene
• Application Number:
  US12/929,796
• Publication Number:
  US 20110198641A1
• Time in Patent Office: 965 Days
• Field of Search: 257/98, 257/99, 257 82- 86
• US Class Current: 257/98
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A semiconductor light-emitting element includes a semiconductor laminated structure including a light-emitting layer sandwiched between first and second conductivity type layers for extracting an emitted light from the light-emitting layer on a side of the second conductivity type layer, a transparent electrode in ohmic contact with the second conductivity type layer, an insulation layer formed on the transparent electrode, an upper electrode for wire bonding formed on the insulation layer, a lower electrode that penetrates the insulation layer, is in ohmic contact with the transparent electrode and the electrode for wire bonding, and has an area smaller than that of the upper electrode in top view, and a reflective portion for reflecting at least a portion of light transmitted through a region of the transparent electrode not in contact with the lower electrode.

Claims

1. A semiconductor light-emitting element, comprising:

a semiconductor laminated structure comprising a light-emitting layer sandwiched between first and second conductivity type layers for extracting an emitted light from the light-emitting layer on a side of the second conductivity type layer;

a transparent electrode in ohmic contact with the second conductivity type layer;

an insulation layer formed on the transparent electrode;

an upper electrode for wire bonding formed on the insulation layer;

a lower electrode that penetrates the insulation layer, is in ohmic contact with the transparent electrode and the upper electrode for wire bonding, and has an area smaller than that of the upper electrode in a top view; and

a reflective portion for reflecting at least a portion of light transmitted through a region of the transparent electrode that is not in contact with the lower electrode,

wherein the lower electrode includes a plurality of lower electrodes that are each disposed to form an island in the top view.

2. The semiconductor light-emitting element according to claim 1, wherein the reflective portion is formed in the insulation layer so as to have a reflectance to light emitted from the light-emitting layer higher than that of the upper electrode and so as not to be in contact with the transparent electrode, the upper electrode, and the lower electrode.

3. The semiconductor light-emitting element according to claim 2, wherein the upper electrode is integrally formed with the lower electrode.

4. The semiconductor light-emitting element according to claim 2, wherein the lower electrode comprises a pad electrode that is in ohmic contact with the transparent electrode.

5. The semiconductor light-emitting element according to claim 2, wherein the upper electrode includes a bonding region for connecting a bonding wire and a linear extension region extending from the bonding region, and

wherein the reflective portion is formed under the bonding region and the extension region.

6. The semiconductor light-emitting element according to claim 2, wherein the upper electrode includes a bonding region for connecting a bonding wire and a linear extension region extending from the bonding region, and

wherein the reflective portion is formed under the extension region.

7. The semiconductor light-emitting element according to claim 2, wherein the upper electrode includes a bonding region for connecting a bonding wire and a linear extension region extending from the bonding region, and

wherein the reflective portion is formed under the bonding region.

8. The semiconductor light-emitting element according to claim 2, wherein the upper electrode includes a bonding region for connecting a bonding wire and a linear extension region extending from the bonding region, and

wherein a region of the reflective portion under the extension region comprises a linear region formed along a length direction of the extension region so as to have a width less than 230% of a width of the extension region.

9. The semiconductor light-emitting element according to claim 1, wherein the reflective portion is formed as a lower portion of or an entire portion of the upper electrode so that a reflectance to the light emitted from the light-emitting layer is higher than that of the lower electrode.

10. The semiconductor light-emitting element according to claim 9, wherein an adhesion of the upper electrode to the insulation layer is higher than that of the lower electrode.

11. The semiconductor light-emitting element according to claim 10, wherein the first and second conductivity type layers comprise n-type and p-type semiconductor layers, respectively,

wherein the first and second conductivity type layers and the light-emitting layer comprise a nitride compound semiconductor,

wherein the transparent electrode comprises a conductive oxide, and

wherein the lower electrode comprises a lower pad electrode in ohmic contact with the transparent electrode and an upper pad electrode in ohmic contact with the lower pad electrode.

12. The semiconductor light-emitting element according to claim 11, further comprising:

an n-electrode comprising a lower n-electrode in ohmic contact with the first conductivity type layer and an upper n-electrode in ohmic contact with the lower n-electrode.

13. The semiconductor light-emitting element according to claim 2, wherein the upper electrode includes a bonding region for connecting a bonding wire and a linear extension region extending from the bonding region, and

wherein the reflective portion is formed under and over the extension region.

14. The semiconductor light-emitting element according to claim 2, wherein the upper electrode includes a bonding region for connecting a bonding wire and a linear extension region extending from the bonding region, and

wherein the reflective portion is formed under the bonding region, and under and over the extension region.

15. The semiconductor light-emitting element according to claim 1, wherein the plurality of lower electrodes are each disposed to form a dot in the top view.

16. The semiconductor light-emitting element according to claim 1, wherein the semiconductor light-emitting element is face-up mounted.

17. The semiconductor light-emitting element according to claim 1, wherein the insulation layer is disposed on a bottom surface of the reflective portion.

18. The semiconductor light-emitting element according to claim 16, wherein the lower electrode is disposed on the bottom surface of the reflective portion.

19. The semiconductor light-emitting element according to claim 16, wherein the bottom surface of the reflective portion comprises a lowermost surface of the reflective portion and is disposed above a top surface of the insulation layer.

20. The semiconductor light-emitting element according to claim 1, wherein the lower electrode is disposed on a bottom surface of the reflective portion.

21. The semiconductor light-emitting element according to claim 1, wherein a bottom surface of the reflective portion comprises a lowermost surface of the reflective portion and is disposed above a top surface of the insulation layer.