Light emitting diode with Bragg reflector

• US 10,038,121 B2
• Filed: 02/17/2016
• Issued: 07/31/2018
• Est. Priority Date: 02/17/2015
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Genesis Photonics Inc.
• Inventors: Huang, Yi-Ru, Chuang, Tung-Lin, Lan, Yan-Ting, Hsu, Sheng-Tsung, Shen, Chih-Ming, Huang, Jing-En, Lai, Teng-Hsien, Mai, Hung-Chuan, Huang, Kuan-Chieh, Ting, Shao-Ying
• Primary Examiner(s): Sandvik, Benjamin
• Assistant Examiner(s): Khan, Farid
• Application Number:
  US15/045,279
• Publication Number:
  US 20160247974A1
• Time in Patent Office: 895 Days
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A light emitting diode including a first-type semiconductor layer, an emitting layer, a second-type semiconductor layer, a first electrode, a second electrode, and a Bragg reflector structure. The emitting layer is configured to emit a light beam and is located between the first-type semiconductor layer and the second-type semiconductor layer. The light beam has a peak wavelength in a light emitting wavelength range. The first-type semiconductor layer, the emitting layer, and the second-type semiconductor layer are located on a same side of the Bragg reflector structure. A reflectance of the Bragg reflector structure is greater than or equal to 95% in a reflective wavelength range at least covering 0.8X nm to 1.8X nm, and X is the peak wavelength of the light emitting wavelength range.

Claims

1. A light emitting diode, comprising:

a first-type semiconductor layer;

an emitting layer, configured to emit a light beam, the light beam has a peak wavelength in a light emitting wavelength range;

a second-type semiconductor layer, wherein the emitting layer is located between the first-type semiconductor layer and the second-type semiconductor layer;

a first electrode electrically connected to the first-type semiconductor layer;

a second electrode electrically connected to the second-type semiconductor layer; and

a Bragg reflector structure, the first electrode and the second electrode are both located on a same side of the Bragg reflector structure, and a reflectance of the Bragg reflector structure is greater than or equal to 95% in a reflective wavelength range at least covering 0.8(X) nm to 1.8(X) nm, wherein X is the peak wavelength of the light emitting wavelength range,

wherein the Bragg reflector structure comprises a plurality of primary stacked layers and at least one buffer stacked layer, the at least one buffer stacked layer is located between the two adjacent primary stacked layers,

wherein the Bragg reflector structure further comprises at least one repair stacked layer, the at least one repair stacked layer is adjacent to one of the primary stacked layer and the at least one buffer stacked layer.

2. The light emitting diode as recited in claim 1, wherein the Bragg reflector structure comprises a plurality of first refractive layers and a plurality of second refractive layers, the first refractive layers and the second refractive layers are stacked alternately, and a refractive index of each of the first refractive layers is different from a refractive index of each of the second refractive layers.

3. The light emitting diode as recited in claim 2, wherein a material of each of the first refractive layers comprises tantalum pentoxide (Ta₂O₅), zirconium dioxide (ZrO₂), niobium pentoxide (Nb₂O₅), hafnium oxide (HfO₂), titanium dioxide (TiO₂), or combinations thereof.

4. The light emitting diode as recited in claim 2, wherein a material of each of the second refractive layers comprises combinations of silicon dioxide (SiO₂).

5. The light emitting diode as recited in claim 2, wherein a thickness of the first refractive layers and a thickness of the second refractive layers gradually change from a side of the Bragg reflector structure toward another side.

6. The light emitting diode as recited in claim 1, wherein the first-type semiconductor layer comprises a first portion and a second portion, the emitting layer is stacked on the first portion, the second portion extends outward from the first portion to protrude from an area of the emitting layer, so as to electrically connect with the first electrode, wherein the first electrode, the emitting layer, the second-type semiconductor layer, and the second electrode are located on a first side of the first-type semiconductor layer.

7. The light emitting diode as recited in claim 6, wherein the Bragg reflector structure is located on a second side of the first-type semiconductor layer, and the first side and the second side are opposite to each other.

8. The light emitting diode as recited in claim 7, further comprising a growth substrate, the first-type semiconductor layer, the emitting layer, and the second-type semiconductor layer are sequentially stacked on a first surface of the growth substrate, the Bragg reflector structure is disposed on a second surface of the growth substrate, and the first surface and the second surface are opposite to each other.

9. The light emitting diode as recited in claim 6, wherein the Bragg reflector structure is located on the first side of the first-type semiconductor layer, the Bragg reflector structure is at least located between the second electrode and the second-type semiconductor layer, the Bragg reflector structure comprises a plurality of through openings, and the second electrode is filled into the through openings to electrically connect with the second-type semiconductor layer.

10. The light emitting diode as recited in claim 9, further comprising a conductive layer disposed between the Bragg reflector structure and the second-type semiconductor layer, and the second electrode contacts the conductive layer by filling into the through openings.

11. The light emitting diode as recited in claim 10, further comprising a plurality of insulation patterns disposed between the conductive layer and the second-type semiconductor layer, the insulation patterns correspond to the through openings such that an area of the conductive layer outside of the insulation patterns contacts the second-type semiconductor layer.

12. The light emitting diode as recited in claim 9, further comprising a growth substrate, the first-type semiconductor layer, the emitting layer, the second-type semiconductor layer, and the Bragg reflector structure are sequentially stacked on a first surface of the growth substrate.

13. The light emitting diode as recited in claim 9, further comprising a first insulating layer and a second insulating layer, the Bragg reflector structure is located between the first insulating layer and the second insulating layer, the first insulating layer is located between the Bragg reflector structure and the second-type semiconductor layer, and the second insulating layer is located between the Bragg reflector structure and the second electrode.

14. The light emitting diode as recited in claim 1, wherein the peak wavelength falls in a range of 320 nm to 420 nm.

15. The light emitting diode as recited in claim 1, wherein the peak wavelength falls in a range of 420 nm to 650 nm.

16. The light emitting diode as recited in claim 1, wherein the peak wavelength falls in a range of 500 nm to 550 nm.

17. The light emitting diode as recited in claim 1, wherein each of the primary stacked layers comprises a plurality of first refractive layers and a plurality of second refractive layers, the first refractive layers and the second refractive layers are stacked alternately, a refractive index of each of the first refractive layers is different from a refractive index of each of the second refractive layers, the first refractive layers in the same primary stacked layer have a same thickness, and the second refractive layers in the same primary stacked layer have a same thickness.

18. The light emitting diode as recited in claim 17, wherein the at least one buffer stacked layer comprises a plurality of third refractive layers and a plurality of fourth refractive layers, the third refractive layers and the fourth refractive layers are stacked alternately, a refractive index of each of the third refractive layers is different from a refractive index of each of the fourth refractive layers, and a thickness of the third refractive layers and a thickness of the fourth refractive layers are different from the thickness of the first refractive layers and the thickness of the second refractive layers.

19. The light emitting diode as recited in claim 18, wherein a material of the third refractive layers is the same as a material of the first refractive layers, and a material of the fourth refractive layers is the same as a material of the second refractive layers.

20. The light emitting diode as recited in claim 1, wherein a material composition of the at least one repair stacked layer is the same as the one of the primary stacked layer and the at least one buffer stacked layer.

21. The light emitting diode as recited in claim 20, wherein the light emitting wavelength range of the light beam completely falls in the reflecting wavelength range of the Bragg reflector structure.