Light-emitting device

• US 9,231,151 B2
• Filed: 09/14/2012
• Issued: 01/05/2016
• Est. Priority Date: 07/28/2006
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Hsu, Ta-Cheng, Yang, Ya-Lan, Su, Ying-Yong, Yeh, Ching-Shian, Huang, Chao-Shun, Lee, Ya-Ju
• Primary Examiner(s): Patel, Nimeshkumar
• Assistant Examiner(s): Lee, Brenitra M
• Application Number:
  US13/618,544
• Publication Number:
  US 20130009188A1
• Time in Patent Office: 1,208 Days
• Field of Search: 313495-498
• US Class Current: 1/1
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• 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

A light-emitting device comprises a textured substrate comprising a boundary and a plurality of textured structures within the boundary, wherein the textured structures and the textured substrate are both composed of sapphire; and a light-emitting stack overlaying the textured substrate, comprising a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, wherein each of the plurality of textured structures comprises a top portion having a first top-view shape and a bottom portion parallel to the top portion, the bottom portion having a second top-view shape, wherein the first top-view shape comprises a circle or ellipse and the second top-view shape comprises a polygon, wherein the first top-view shape and the second top-view shape overlap each other, and the textured structures are spaced apart from each other from a top view of the light-emitting device.

Claims

1. A light-emitting device, comprising:

a textured substrate comprising a boundary and a plurality of textured structures within the boundary, wherein the textured structures and the textured substrate are both composed of sapphire; and

a light-emitting stack overlaying the textured substrate, comprising a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer,

wherein each of the plurality of textured structures comprises a top portion having a first top-view shape and a bottom portion parallel to the top portion, the bottom portion having a second top-view shape, wherein the first top-view shape comprises a circle or an ellipse, and the second top-view shape comprises a polygon, wherein the first top-view shape and the second top-view shape overlap each other, and the textured structures are spaced apart from each other from a top view of the light-emitting device.

2. The light-emitting device according to claim 1, wherein the first top-view shape comprises the circle and the second top-view shape comprises a triangle.

3. The light-emitting device according to claim 1, wherein at least one of the top portion and the bottom portion comprises a flat plane.

4. The light-emitting device according to claim 3, wherein the flat plane comprises a sapphire C plane.

5. The light-emitting device according to claim 1, wherein one of the plurality of textured structures further comprises a sidewall portion connecting the top portion and the bottom portion.

6. The light-emitting device according to claim 5, wherein the sidewall portion comprises a plurality of symmetric planes.

7. The light-emitting device according to claim 5, wherein the sidewall portion comprises a plurality of symmetric sapphire R-planes.

8. The light-emitting device according to claim 5, wherein a cross-section of the sidewall portion near the top portion is a curve.

9. The light-emitting device according to claim 5, wherein a cross-section of the sidewall portion near the bottom portion is a curve.

10. The light-emitting device according to claim 5, wherein a cross-section of the bottom portion is rounded.

11. The light-emitting device according to claim 1, wherein the light-emitting stack comprises a III-nitride compound.

12. The light-emitting device according to claim 1, further comprising a semiconductor buffer layer directly formed on the plurality of textured structures of the textured substrate, wherein the semiconductor buffer layer comprises a III-nitride compound.

13. The light-emitting device according to claim 1, wherein the second top-view shape is located within the first top-view shape.