Light-emitting device and manufacturing method thereof

• US 9,871,171 B2
• Filed: 11/07/2014
• Issued: 01/16/2018
• Est. Priority Date: 11/07/2014
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: Epistar Corporation (Ennostar, Inc.)
• Inventors: Hu, Jen-Li, Hsu, Tzu-Chieh
• Primary Examiner(s): Miyoshi, Jesse Y
• Assistant Examiner(s): Hoang, Tuan A
• Application Number:
  US14/535,995
• Publication Number:
  US 20160133796A1
• Time in Patent Office: 1,166 Days
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A light-emitting device comprises a light-emitting structure capable of emitting a light; an electrode formed on a side of the light-emitting structure; a transparent structure formed on a second side of the light-emitting structure, wherein the transparent structure is aligned to a region of the electrode, and comprises a first transparent layer and a second transparent layer around the first transparent layer; a contact structure formed on the second side of the light-emitting structure; and a reflective layer covering the transparent structure and the contact structure.

Claims

1. A light-emitting device, comprising:

a light-emitting structure capable of emitting a light;

an electrode formed on a first side of the light-emitting structure;

a transparent dielectric structure formed on a second side of the light-emitting structure, wherein the transparent dielectric structure is aligned to a region of the electrode, and comprises a first transparent layer and a second transparent layer covering the first transparent layer, wherein the first transparent layer and the second transparent layer have different refractive indices; and

a reflective layer covering the transparent dielectric structure.

2. The light-emitting device of claim 1, wherein the first transparent layer and the second transparent layer both contact the light-emitting structure.

3. The light-emitting device of claim 1, wherein a region where the first transparent layer contacts the light-emitting structure is larger than a region where the second transparent layer contacts the light-emitting structure.

4. The light-emitting device of claim 1, wherein the transparent dielectric structure is formed in a pattern corresponding to a pattern of the electrode.

5. The light-emitting device of claim 1, wherein the transparent dielectric structure comprises a wider width than the electrode.

6. The light-emitting device of claim 1, wherein the first transparent layer has a taper sidewall.

7. The light-emitting device of claim 1, wherein a sidewall of the first transparent layer is inclined to the second side of the light-emitting structure by an angle between 20 and 80°

.

8. The light-emitting device of claim 1, wherein a cross sectional shape of the first transparent layer comprises trapezoid.

9. The light-emitting device of claim 1, wherein the first transparent layer comprises a thickness proportional to a quarter of a dominant wavelength of the light and inversely proportional to a refractive index of the first transparent layer.

10. The light-emitting device of claim 1, wherein the refractive index of the first transparent layer is between 1.5 and 3, and the refractive index of the second transparent layer is lower than 1.5.

11. The light-emitting device of claim 1, wherein an interface between the light-emitting structure and the transparent dielectric structure comprises a rough surface.

12. The light-emitting device of claim 1, wherein the reflective layer comprises a reflectivity higher than 80% with respect to the light emitted from the light-emitting structure.

13. The light-emitting device of claim 1, further comprising a bonding layer and a substrate, wherein the substrate is bonded to the reflective layer by the bonding layer.

14. The light-emitting device of claim 13, wherein a void is formed within the bonding layer or between the bonding layer and the substrate.

15. The light-emitting device of claim 1, wherein a contact structure is formed on the second side of the light-emitting structure.

16. The light-emitting device of claim 15, further comprising a transparent conductive layer covering the transparent dielectric structure and the contact structure, wherein the transparent conductive layer extends into a space between the contact structure and the transparent dielectric structure.

17. The light-emitting device of claim 15, wherein the contact structure is provided to correspond to a region beyond the electrode.

18. The light-emitting device of claim 1, wherein the first transparent layer comprises a thickness thicker than a thickness of the second transparent layer.

19. The light-emitting device of claim 18, wherein a ratio between the thickness of the first transparent layer and the thickness of the second transparent layer ranges from 5 to 20.

20. The light-emitting device of claim 1, wherein the refractive index of the first transparent layer is higher than that of the second transparent layer.