US-12622109-B2 - Light-emitting diode

Abstract

A light-emitting diode includes a semiconductor light-emitting stack, a transparent conductive layer, a first current blocking layer, and a first electrode pad. The semiconductor light-emitting stack includes, in sequence from bottom to top, a second conductivity type semiconductor layer, a light-emitting layer, and a first conductivity type semiconductor layer. The transparent conductive layer is disposed on the first conductivity type semiconductor layer, and is formed with a first opening which is defined by an inner edge of the transparent conductive layer. The first current blocking layer is formed on the first conductivity type semiconductor layer. The first electrode pad is formed on and in contact with both the first current blocking layer and on the first conductivity type semiconductor layer. The first electrode pad has a width not greater than a dimension of the first opening.

Inventors

• Gong Chen
• Su-Hui Lin
• Sheng-Hsien Hsu
• MINYOU HE
• KANG-WEI PENG
• Ling-yuan HONG

Assignees

• XIAMEN SAN'AN OPTOELECTRONICS CO., LTD.

Dates

Publication Date

20260505

Application Date

20230407

Priority Date

20191223

Claims (20)

1. 1 . A light-emitting diode comprising: a semiconductor light-emitting stack which includes, in sequence from bottom to top, a second conductivity type semiconductor layer, a light-emitting layer, and a first conductivity type semiconductor layer; a transparent conductive layer disposed on said first conductivity type semiconductor layer, and formed with a first opening which is defined by an inner edge of said transparent conductive layer; a first current blocking layer formed on said first conductivity type semiconductor layer; and a first electrode pad formed on said first current blocking layer and on said first conductivity type semiconductor layer, said first electrode pad being in contact with both said first current blocking layer and said first conductivity type semiconductor layer, said first electrode pad having a width not greater than a dimension of said first opening.
2. 2 . The light-emitting diode according to claim 1 , further comprising a protective layer which covers said transparent conductive layer, said semiconductor light-emitting stack, and at least a portion of said first electrode pad.
3. 3 . The light-emitting diode according to claim 1 , wherein the width of said first electrode pad is smaller than the dimension of said first opening.
4. 4 . The light-emitting diode according to claim 1 , wherein said first current blocking layer includes at least one block.
5. 5 . The light-emitting diode according to claim 1 , further comprising: a first electrode extension which is connected to an edge of said first electrode pad, and which extends from said edge of said first electrode pad to be disposed on and in contact with said transparent conductive layer; and at least one second current blocking layer disposed between said transparent conductive layer and said semiconductor light-emitting stack.
6. 6 . The light-emitting diode according to claim 5 , which comprises a plurality of said second current blocking layers, two adjacent ones of said second current blocking layers being spaced apart from each other by a first gap.
7. 7 . The light-emitting diode according to claim 1 , wherein said first electrode pad is formed on said first current blocking layer to fully cover an upper surface of said first current blocking layer in a way that said first electrode pad is in contact with said first conductivity type semiconductor layer through a second gap between said first current blocking layer and said transparent conductive layer.
8. 8 . The light-emitting diode according to claim 7 , wherein said second gap has a predetermined width ranging from 0.1 μm to 40 μm.
9. 9 . The light-emitting diode according to claim 1 , wherein an outer peripheral surface of said first electrode pad and said inner edge of said transparent conductive layer are separated by a spacing ranging from 5 μm to 20 μm.
10. 10 . The light-emitting diode according to claim 1 , wherein said first electrode pad has a radial thickness on an outer peripheral surface of said first current blocking layer, the radial thickness ranging from 0.1 μm to 20 μm.
11. 11 . A light-emitting diode comprising: a semiconductor light-emitting stack which includes, in sequence from bottom to top, a second conductivity type semiconductor layer, a light-emitting layer, and a first conductivity type semiconductor layer; a transparent conductive layer disposed on said first conductivity type semiconductor layer, and formed with a first opening which is defined by an inner edge of said transparent conductive layer; a first current blocking layer formed on said first conductivity type semiconductor layer; a first electrode pad formed on said first current blocking layer and on said first conductivity type semiconductor layer, said first electrode pad being in contact with both said first current blocking layer and said first conductivity type semiconductor layer, said first electrode pad having an outer peripheral surface; a spacing formed between said outer peripheral surface of said first electrode pad and said inner edge of said transparent conductive layer; and a protective layer which covers said transparent conductive layer, said semiconductor light-emitting stack, and at least a portion of said first electrode pad, said protective layer being in contact with said first conductivity type semiconductor layer through said spacing.
12. 12 . The light-emitting diode according to claim 11 , wherein said first electrode pad has a width smaller than a dimension of said first opening.
13. 13 . The light-emitting diode according to claim 11 , further comprising: a first electrode extension which is connected to an edge of said first electrode pad, and which extends from said edge of said first electrode pad to be disposed on and in contact with said transparent conductive layer; and at least one second current blocking layer disposed between said transparent conductive layer and said semiconductor light-emitting stack.
14. 14 . The light-emitting diode according to claim 13 , which comprises a plurality of said second current blocking layers, two adjacent ones of said second current blocking layers being spaced apart from each other by a first gap.
15. 15 . The light-emitting diode according to claim 11 , wherein said first electrode pad is formed on said first current blocking layer to fully cover an upper surface of said first current blocking layer in a way that said first electrode pad is in contact with said first conductivity type semiconductor layer through a second gap between said first current blocking layer and said transparent conductive layer.
16. 16 . The light-emitting diode according to claim 11 , wherein said first current blocking layer is surrounded by and spaced apart from said inner edge of said transparent conductive layer by a second gap.
17. 17 . A light-emitting diode comprising: a semiconductor light-emitting stack which includes, in sequence from bottom to top, a second conductivity type semiconductor layer, a light-emitting layer, and a first conductivity type semiconductor layer; a transparent conductive layer disposed on and in contact with said first conductivity type semiconductor layer, said transparent conductive layer being formed with a first opening which is defined by an inner edge of said transparent conductive layer; and a first electrode pad formed on and in contact with said first conductivity type semiconductor layer, said first electrode pad having a width smaller than a dimension of said first opening.
18. 18 . The light-emitting diode according to claim 17 , further comprising: a spacing formed between an outer peripheral surface of said first electrode pad and said inner edge of said transparent conductive layer; and a protective layer which covers said transparent conductive layer, said semiconductor light-emitting stack, and at least a portion of said first electrode pad, said protective layer being in contact with said first conductivity type semiconductor layer through said spacing.
19. 19 . The light-emitting diode according to claim 17 , further comprising a first current blocking layer which is formed on said first conductivity type semiconductor layer and under a portion of a lower surface of said first electrode pad.
20. 20 . The light-emitting diode according to claim 19 , further comprising: a first electrode extension which is connected to an edge of said first electrode pad, and which extends from said edge of said first electrode pad to be disposed on and in contact with said transparent conductive layer; and at least one second current blocking layer disposed between said transparent conductive layer and said semiconductor light-emitting stack.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part application of U.S. patent application Ser. No. 17/130,550, which claims priority of Chinese Utility Model Patent Application No. 201922330841.X, filed on Dec. 23, 2019. The entire content of each of the U.S. and Chinese patent applications is incorporated herein by reference. FIELD The disclosure relates to a semiconductor device, and more particularly to a light-emitting diode. BACKGROUND Light-emitting diode (LED) chips have advantages of long service life and low power consumption. As LED technology matures, LED chips are widely applied in various fields. An existing LED chip generally includes a substrate, a first conductivity type semiconductor layer, an active layer, a second conductivity type semiconductor layer, a first electrode formed on the first conductivity type semiconductor layer, a second electrode formed on the second conductivity type semiconductor layer, and a transparent conductive layer covering on the first conductivity type semiconductor layer. The first electrode of a conventional face-up LED chip generally includes a first electrode pad and a first electrode extension. At least an edge of a lower surface of the first electrode pad is in contact with the transparent conductive layer, and a current blocking layer is provided beneath the transparent conductive layer that is located beneath the lower surface of the first electrode pad. Typically, the current blocking layer extends beyond a covering area of the lower surface of the first electrode pad, which is in contact with the transparent conductive layer so as to block a vertical current transfer between the edge of the lower surface of the first electrode pad and the first conductivity type semiconductor layer. However, the conventional lateral LED chip may have some shortcomings. For example, the first electrode pad has a low adhesion to both the transparent conductive layer and the current blocking layer, and thus, in a subsequent wiring process, might have poor wiring reliability or might be detached upon application of an external force. In addition, in the case that the current blocking layer extends beyond the covering area of the first electrode pad, when forming an opening on a protective layer covering on the first electrode pad, an etchant might have an easy access to the current blocking layer through an outer periphery of the first electrode pad and the transparent conductive layer, which might cause the current blocking layer to be etched by the etchant, thereby lowering the reliability of the conventional lateral LED chip. SUMMARY Therefore, an object of the disclosure is to provide a light-emitting diode that can alleviate at least one of the drawbacks of the prior art. According to a first aspect of the disclosure, a light-emitting diode includes a semiconductor light-emitting stack, a transparent conductive layer, a first current blocking layer, and a first electrode pad. The semiconductor light-emitting stack includes, in sequence from bottom to top, a second conductivity type semiconductor layer, a light-emitting layer, and a first conductivity type semiconductor layer. The transparent conductive layer is disposed on the first conductivity type semiconductor layer, and is formed with a first opening which is defined by an inner edge of the transparent conductive layer. The first current blocking layer is formed on the first conductivity type semiconductor layer. The first electrode pad is formed on and in contact with both the first current blocking layer and on the first conductivity type semiconductor layer. The first electrode pad has a width not greater than a dimension of the first opening. According to a second aspect of the disclosure, a light-emitting diode includes a semiconductor light-emitting stack, a transparent conductive layer, a first current blocking layer, a first electrode pad, a spacing, and a protective layer. The semiconductor light-emitting stack includes, in sequence from bottom to top, a second conductivity type semiconductor layer, a light-emitting layer, and a first conductivity type semiconductor layer. The transparent conductive layer is disposed on the first conductivity type semiconductor layer, and is formed with a first opening which is defined by an inner edge of the transparent conductive layer. The first current blocking layer is formed on the first conductivity type semiconductor layer. The first electrode pad is formed on the first current blocking layer and on the first conductivity type semiconductor layer. The first electrode pad is in contact with both the first current blocking layer and the first conductivity type semiconductor layer. The first electrode pad has an outer peripheral surface. The spacing is formed between the outer peripheral surface of the first electrode pad and the inner edge of the transparent conductive layer. The protective layer covers the transparent conductive laye