LIGHT EMITTING DIODE STRUCTURE

• US 20160064617A1
• Filed: 08/27/2014
• Published: 03/03/2016
• Est. Priority Date: 08/27/2014
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: Formosa Epitaxy Incorporated (Ennostar, Inc.)
• Inventors: Feng, Hui-Ching, Hsu, Chien-Pin, Pan, Shyi-Ming, Yang, Cheng-Kuang, Yu, Kuo-Hui
• Granted Patent: US 10,074,777 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

A light emitting diode (LED) structure including a stacked semiconductor layer, a contact layer and a dielectric reflective layer is provided. The stacked semiconductor layer includes a first type doped layer, a second type doped layer and an active layer disposed between the first type doped layer and the second type doped layer, wherein the first type doped layer, the active layer and the second type doped layer are penetrated by a plurality of recesses. The contact layer is disposed on the second type doped layer. The dielectric reflective layer is disposed on the contact layer and extended into the recesses to connect the contact layer and the first type doped layer with a coverage rate equal to or less than 60% from a top view of the LED structure.

Claims

1. A light emitting diode (LED) structure, comprising:

a stacked semiconductor layer comprising

a first type doped layer;

a second type doped layer;

an active layer disposed between the first type doped layer and the second type doped layer, wherein the first type doped layer, the active layer and the second type doped layer are penetrated by a plurality of recesses;

a contact layer disposed on the second type doped layer; and

a dielectric reflective layer connecting to the contact layer and the first type doped layer with a coverage rate equal to or less than 60% from a top view of the LED structure.

2. The LED structure as claimed in claim 1, further comprising an electrode layer disposed on the dielectric reflective layer, wherein the electrode layer comprises a first electrode region and a second electrode region, and the first electrode region and the second electrode region are separated by a groove.

3. The LED structure as claimed in claim 2, further comprising a plurality of caves with corresponding openings on a top surface of the LED structure, wherein the caves are disposed on the stacked semiconductor layer.

4. The LED structure as claimed in claim 3, wherein the second electrode region of the electrode layer electrically connects to the contact layer through at least some of the caves.

5. The LED structure as claimed in claim 4, further comprising a patterned mirror layer disposed on the contact layer, wherein the patterned mirror layer connects to at least some of the caves and the contact layer, such that the second electrode region of the electrode layer electrically connects to the contact layer through the corresponding caves and the patterned mirror layer connecting to the corresponding caves.

6. The LED structure as claimed in claim 5, wherein the dielectric reflective layer covers a part of the patterned mirror layer, where the patterned mirror layer does not connect to the caves.

7. The LED structure as claimed in claim 2, further comprising a conductive layer disposed between the dielectric reflective layer and the electrode layer, wherein the conductive layer connects to the first type doped layer from at least some of the recesses, and the first electrode region of the electrode layer connects to a part of the conductive layer.

8. The LED structure as claimed in claim 7, further comprising an insulation layer disposed between the second electrode region of the electrode layer and the conductive layer.

9. The LED structure as claimed in claim 8, wherein the insulation layer further disposed between the first electrode region of the electrode layer and the conductive layer, where the first electrode region of the electrode layer does not connect to the conductive layer.

10. The LED structure as claimed in claim 1, further comprising a substrate with a surface where the stacked semiconductor layer disposed on, wherein a part of the surface of the substrate is exposed from the stacked semiconductor layer to form an exposed area, and the dielectric reflective layer further covers at least a part of the exposed area of the substrate.

11. The LED structure as claimed in claim 1, wherein the dielectric reflective layer comprises a low refractive index layer, and the material of the low refractive index layer is selected from SiO₂, MgF₂, CaF₂ or any combinations thereof.

12. The LED structure as claimed in claim 11, wherein the dielectric reflective layer is a Distributed Bragg Reflector (DBR) and further comprises a high refractive index layer, and the material of the high refractive index layer is selected from TiO₂, ZnSe, Si₃N₄, Nb₂O₅, Ta₂O₅ or any combinations thereof.

13. The LED structure as claimed in claim 1, wherein the coverage rate is further equal to or less than 30%.

14. The LED structure as claimed in claim 3, wherein at least a part of the caves are stripe-shaped caves, and extensional directions of the stripe-shaped caves are parallel to each other.

15. The LED structure as claimed in claim 3, wherein at least a part of the caves are circular-shaped caves and in an array arrangement.

16. The LED structure as claimed in claim 1, wherein a material of the contact layer is selected from indium tin oxide (ITO), cerium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO) indium zinc oxide (IZO), zinc oxide (ZnO), cadmium tin oxide, ZnGa₂O₄, SnO₂:

Sb, Ga₂O₃;

Sn, AgInO₂;

Sn, In₂O₃;

Zn, CuAlO₂, LaCuOS, NiO, or CuGaO₂, SrCu₂O₂, Ag, Au, Al, Ti, Pd, graphene or any combinations thereof.

17. The LED structure as claimed in claim 4, wherein the second electrode region of the electrode layer connects to the contact layer through the caves.

18. The LED structure as claimed in claim 3, further comprising a conductive layer disposed between the dielectric reflective layer and the electrode layer, wherein the conductive layer is connected to the first type doped layer through at least some of the recesses, and the first electrode region of the electrode layer is connected to a part of the conductive layer through at least some of the caves.

19. The LED structure as claimed in claim 18, wherein one of the caves where the second electrode region of the electrode layer is electrically connected to the contact layer and one of the recesses where the conductive layer is connected to the first type doped layer are adjacently disposed.

20. The LED structure as claimed in claim 18, wherein at least some of the caves where the second electrode region of the electrode layer is electrically connected to the contact layer and at least some of the recesses where the conductive layer is connected to the first type doped layer are alternately disposed.