Light-emitting device

• US 10,396,243 B2
• Filed: 07/09/2018
• Issued: 08/27/2019
• Est. Priority Date: 02/20/2014
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Chung, Chien-Kai, Chiu, Po-Shun, Wang, Hsin-Ying, Kuo, De-Shan, Ko, Tsun-Kai, Huang, Yu-Ting
• Primary Examiner(s): Ho, Tu-Tu V
• Application Number:
  US16/030,437
• Publication Number:
  US 20180315889A1
• Time in Patent Office: 414 Days
• Field of Search: 257 99
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• 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
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body

Abstract

A light-emitting device includes: a rectangular shape with a first side, a second side opposite to the first side, and a third side connecting the first side and the second side; a light-emitting stack, comprising a lower semiconductor layer, an upper semiconductor layer, and an active layer between the lower semiconductor layer and the upper semiconductor layer; a first electrode formed on the lower semiconductor layer, comprising a first electrode pad and a first extension electrode; a second electrode formed on the upper semiconductor layer, comprising a second electrode pad and a second extension electrode; and a first current blocking layer formed between the lower semiconductor layer and the first electrode pad, wherein the first current blocking layer comprises a top surface and side surfaces; wherein the first electrode pad covers the top surface and the side surfaces of the first current blocking layer and contacts the lower semiconductor layer.

Claims

1. A light-emitting device, comprising:

a rectangular shape with a first side, a second side opposite to the first side, and a third side connecting the first side and the second side;

a light-emitting stack, comprising a lower semiconductor layer, an upper semiconductor layer, and an active layer between the lower semiconductor layer and the upper semiconductor layer;

a first electrode formed on the lower semiconductor layer, comprising a first electrode pad and a first extension electrode;

a second electrode formed on the upper semiconductor layer, comprising a second electrode pad and a second extension electrode; and

a first current blocking layer formed between the lower semiconductor layer and the first electrode pad, wherein the first current blocking layer comprises a top surface and side surfaces;

wherein the first electrode pad covers the top surface and the side surfaces of the first current blocking layer and contacts the lower semiconductor layer.

2. The light-emitting device according to claim 1, wherein the second extension electrode comprises a plurality of branches, and the first extension electrode is disposed between the plurality of branches.

3. The light-emitting device according to claim 1, wherein the first extension electrode comprises a first section extends from the first electrode pad toward the second electrode pad and a second section extends from the first electrode pad toward a direction away from the second electrode pad.

4. The light-emitting device according to claim 3, wherein the length of the first side is X, the length of the third side is Y, the length of the first section is a, and the length of the second section is b, and (a/b)=C(Y/X)−

L, and C is a value between 1.5 and 2, and L is a value between 1 and 1.05.

5. The light-emitting device of claim 4, wherein Y>

X.

6. The light-emitting device of claim 3, wherein the length of the first section is a, and the length of the second section is b;

and wherein a>

b.

7. The light-emitting device of claim 3, wherein the second extension electrode comprises a first branch with a first end and a second branch with a second end;

and wherein the second section extends without crossing an imaginary line linking the first end and the second end.

8. The light-emitting device of claim 3, wherein the second electrode pad is adjacent to the second side, and the first section and the second section are parallel to the third side.

9. The light-emitting device of claim 1, wherein the first extension electrode is parallel with the third side and the second extension electrode is an arc.

10. The light-emitting device of claim 1, wherein:

the first electrode pad is formed adjacent to the third side;

the second electrode pad is formed adjacent to the second side; and

the first extension electrode extends from the first electrode pad in a direction away from the third side and bended toward the second side.

11. The light-emitting device of claim 10, wherein:

the second extension electrode comprises a first branch and a second branch respectively extended from the second electrode pad;

a distance between the first electrode pad and the third side is smaller than a distance between the second electrode pad and the third side; and

an end portion of the first branch comprises a first arc bending to the third side and a minimum distance between the first branch and the first side is smaller than a minimum distance between the second branch and the first side.

12. The light-emitting device of claim 11, wherein the second branch comprises a second arc connecting the second electrode pad and a stripe connecting to the second arc, and the stripe is parallel with the third side.

13. The light-emitting device according to claim 1, further comprising a transparent conductive layer formed on the upper semiconductor layer.

14. The light-emitting device according to claim 1, further comprising a second current blocking layer under the second electrode pad.

15. The light-emitting device according to claim 1, wherein the first electrode pad has a width larger than that of the first current blocking layer.

16. The light-emitting device according to claim 1, wherein the first current blocking layer is embedded in the first electrode pad.