LED with current spreading layer and fabrication method

Patent metadata

Field	Value
Publication number	US-9705033-B2
Application number	US-201414531973-A
Country	US
Kind code	B2
Filing date	Nov 3, 2014
Priority date	Jun 19, 2012
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

A lighting emitting diode including: an n side layer and a p side layer formed by nitride semiconductors respectively; an active layer comprising a nitride semiconductor is between the n side layer and the p side layer; wherein, the n-side layer is successively laminated by an extrinsically-doped buffer layer and a compound multi-current spreading layer; the compound multi-current spreading layer is successively-laminated by a first current spreading layer, a second current spreading layer and a third current spreading layer; the first current spreading layer and the third current spreading layer are alternatively-laminated layers comprising a u-type nitride semiconductor layer and an n-type nitride semiconductor layer; the second current spreading layer is a distributed insulation layer formed on the n-type nitride semiconductor layer; and the first current spreading layer is adjacent to the extrinsically-doped buffer layer; and the third current spreading layer is adjacent to the active layer.

First claim

The invention claimed is:

1. A light emitting diode (LED) comprising:
an n side layer and a p side layer formed with nitride semiconductors, respectively;
an active layer comprising a nitride semiconductor between the n side layer and the p side layer;
wherein:
the n side layer is successively laminated by an extrinsically-doped buffer layer and a compound multi-current spreading layer; the compound multi-current spreading layer is successively-laminated by a first current spreading layer, a second current spreading layer and a third current spreading layer;
the first current spreading layer and the third current spreading layer each are alternatively-laminated layers comprising a u-type nitride semiconductor layer and an n-type nitride semiconductor layer; the second current spreading layer is a distributed insulation layer formed on the n-type nitride semiconductor layer; and
the first current spreading layer is on the extrinsically-doped buffer layer, and the third current spreading layer is adjacent to the active layer;

wherein the third current spreading layer is configured for a two-dimensional spreading of current from distributed point current sources formed by the second current spreading layer; and
wherein the extrinsically-doped buffer layer is configured for directly coupling to an electrode metal layer.

2. The LED of claim 1 , wherein the compound multi-current spreading layer further comprises a Si-doped n-type nitride gradient semiconductor layer between the second current spreading layer and the third current spreading layer.

3. The LED of claim 2 , further comprising a conductive substrate, and a vertical light-emitting epitaxial structure including the p side layer, the active layer and the n side layer disposed over the conductive substrate.

4. The LED of claim 2 , wherein the distributed insulation layer comprises insulation portions separated with preset intervals.

5. The LED of claim 2 , wherein a film thickness of the compound multi-current spreading layer is about 1000 Å-100000 Å.

6. The LED of claim 2 , wherein a film thickness of the second current spreading layer is about 100 Å-5000 Å.

7. The LED of claim 2 , wherein a film thickness of the Si-doped n-type nitride gradient semiconductor layer is about 200 Å-5000 Å.

8. The LED of claim 2 , wherein the Si-doped n-type nitride gradient semiconductor layer is formed through second epitaxial growth and the Si-doping concentration gradually varies from 1×10 17 cm −3 to 5×10 19 cm −3 .

9. The LED of claim 8 , wherein, the Si-doped n-type nitride gradient semiconductor layer is formed through secondary epitaxial growth and the Si-doping concentration gradually varies from 5×10 17 cm −3 to 1×10 19 cm −3 .

10. The LED of claim 2 , wherein a film thickness of the first current spreading layer and the third current spreading layer is about 350 Å-45000 Å; a film thickness ratio between the u-type nitride semiconductor layer and the n-type nitride semiconductor layer is more than 0.8 and the number of laminated cycles is 1-100.

11. The LED of claim 10 , wherein a film thickness of the first current spreading layer is about 10000 Å-40000 Å; a film thickness ratio between the u-type nitride semiconductor layer and the n-type nitride semiconductor layer is 1.5:1 and the number of laminated cycles is 40.

12. The LED of claim 11 , wherein a film thickness of the third current spreading layer is about 4000 Å-18000 Å; a film thickness ratio between the u-type nitride semiconductor layer and the n-type nitride semiconductor layer is 1:1 and a number of laminated cycles is 18.

13. The LED of claim 1 , wherein in the first current spreading layer and the third current spreading layer, the Si-doping concentration in the u-type nitride semiconductor layer is less than 5×10 17 cm −3 and the Si-doping concentration in the n-type nitride semiconductor layer is more than 1×10 18 cm −3 .

14. A system comprising one or more light emitting diodes (LEDs), wherein each LED comprises:
an n-side layer and a p-side layer formed with nitride semiconductors, respectively;
an active layer comprising a nitride semiconductor between the n-side layer and the p-side layer;
wherein:
the n-side layer is successively laminated by an extrinsically-doped buffer layer and a compound multi-current spreading layer; the compound multi-current spreading layer is successively-laminated by a first current spreading layer, a second current spreading layer and a third current spreading layer;
the first current spreading layer and the third current spreading layer each are alternatively-laminated layers comprising a u-type nitride semiconductor layer and an n-type nitride semiconductor layer; the second current spreading layer is a distributed insulation layer formed on the n-type nitride semiconductor layer; and
the first current spreading layer is on the extrinsically-doped buffer layer, and the third current spreading layer is adjacent to the active layer;

wherein the third current spreading layer is configured for a two-dimensional spreading of current from distributed point current sources formed by the second current spreading layer; and
wherein the extrinsically-doped buffer layer is configured for directly coupling to an electrode metal layer.

15. The system of claim 14 , wherein the compound multi-current spreading layer further comprises a Si-doped n-type nitride gradient semiconductor layer between the second current spreading layer and the third current spreading layer.

16. A fabrication method for a light emitting diode (LED), comprising:
providing a growth substrate and forming an n-side layer with a nitride semiconductor over the substrate;
forming an active layer with a nitride semiconductor over the n-side layer;
forming a p-side layer with a nitride semiconductor over the active layer to form an epitaxial structure;
wherein:
the n-side layer is successively laminated by an extrinsically-doped buffer layer and a compound multi-current spreading layer; the compound multi-current spreading layer is successively-laminated by a first current spreading layer, a second current spreading layer and a third current spreading layer;
the first current spreading layer and the third current spreading layer are alternatively-laminated layers comprising a u-type nitride semiconductor layer and an n-type nitride semiconductor layer; the second current spreading layer is a distributed insulation layer formed on the n-type nitride semiconductor layer; and
the first current spreading layer is on the extrinsically-doped buffer layer, and the third current spreading layer is adjacent to the active layer;

wherein the resulting LED comprises:
the n side layer and the p side layer formed with nitride semiconductors, respectively;
the active layer comprising a nitride semiconductor between the n side layer and the p side layer;
wherein:
the n side layer is successively laminated by an extrinsically-doped buffer layer and a compound multi-current spreading layer; the compound multi-current spreading layer is successively-laminated by the first current spreading layer, the second current spreading layer and the third current spreading layer;
the first current spreading layer and the third current spreading layer each are alternatively-laminated layers comprising a u-type nitride semiconductor layer and an n-type nitride semiconductor layer; the second current spreading layer is a distributed insulation layer formed on the n-type nitride semiconductor layer; and
the first current spreading layer is adjacent to the extrinsically-doped buffer layer, and

Assignees

• Xiamen Sanan Optoelectronics Technology Co Ltd

Inventors

• Yeh Meng-Hsin
• Wu Jyh-Chiarng

Classifications

• H01L33/14 Primary

  Electricity · mapped topic

• H01L33/0025

  Electricity · mapped topic

• H01L33/007

  Electricity · mapped topic

• H01L33/0079

  Electricity · mapped topic

• H01L33/0075

  Electricity · mapped topic