Light-emitting device having a patterned substrate and the method thereof

• US 8,648,522 B2
• Filed: 08/20/2010
• Issued: 02/11/2014
• Est. Priority Date: 07/28/2006
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: Epistar Corporation (Ennostar, Inc.)
• Inventors: Hsu, Ta-Cheng, Yang, Ya-Lan, Su, Ying-Yong, Yeh, Ching-Shian, Huang, Chao-Shun, Lee, Ya-Ju
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): Lee, Brenitra M
• Application Number:
  US12/860,599
• Publication Number:
  US 20100314991A1
• Time in Patent Office: 1,271 Days
• Field of Search: 313495-498
• US Class Current: 313/498
• 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

This disclosure provides a light-emitting device including a patterned substrate and the manufacturing method thereof. The patterned substrate has a plurality of depressions and/or extrusions for scattering light emitted from a light-emitting layer. Each of the plurality of depressions and/or extrusions comprises a top portion, a bottom portion, and a sidewall portion enclosing the top portion and the bottom portion, and at least part of the sidewall portion comprises a curve. In a preferred embodiment, the light-emitting device further comprises a rough surface formed on at least one of the top portion, the bottom portion, and the sidewall portion.

Claims

1. A light-emitting device, comprising:

a patterned substrate having an uneven surface composed of a plurality of extrusions;

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

wherein at least one of the plurality of extrusions comprises a top portion, a bottom portion, and a sidewall portion formed between the top portion and the bottom portion, and wherein a surface roughness of the top portion is larger than a surface roughness of the sidewall portion.

2. The light-emitting device according to claim 1, wherein each of the top portion and the bottom portion further comprises a rough surface comprising a regular pattern or an irregular pattern.

3. The light-emitting device according to claim 2, wherein at least part of the sidewall portion comprises a curve.

4. The light-emitting device according to claim 2, wherein the sidewall portion comprises a plurality of symmetric planes.

5. The light-emitting device according to claim 1, wherein the substrate comprises sapphire.

6. The light-emitting device according to claim 5, wherein the bottom portion comprises a sapphire C plane.

7. The light-emitting device according to claim 5, wherein the sidewall portion comprises at least three symmetric sapphire R planes.

8. The light-emitting device according to claim 1, wherein the top-view pattern of the extrusion comprises circle or ellipse.

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

10. The light-emitting device according to claim 1, wherein a ratio of an area of the bottom portion to an area of the top portion is substantially between 0.15 and 0.75.