Group III nitride semiconductor light-emitting device and production method therefor

Patent metadata

Field	Value
Publication number	US-10833223-B2
Application number	US-201816184821-A
Country	US
Kind code	B2
Filing date	Nov 8, 2018
Priority date	Nov 10, 2017
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

To provide a Group III nitride semiconductor light-emitting device exhibiting the improved light extraction efficiency as well as reducing the influence of polarization that a p-type conductivity portion and an n-type conductivity portion occur in the AlGaN layer caused by the Al composition variation, and a production method therefor. A first p-type contact layer is a p-type AlGaN layer. A second p-type contact layer is a p-type AlGaN layer. The Al composition in the first p-type contact layer is reduced with distance from a light-emitting layer. The Al composition in the second p-type contact layer is reduced with distance from the light-emitting layer. The Al composition in the second p-type contact layer is lower than that in the first p-type contact layer. The Al composition variation rate to the unit thickness in the second p-type contact layer is higher than that in the first p-type contact layer.

First claim

What is claimed is:

1. A Group III nitride semiconductor light-emitting devices comprising:
a substrate;
an n-type semiconductor layer on the substrate;
a light-emitting layer on the n-type semiconductor layer; and
a p-type semiconductor layer on the light-emitting layer, wherein
an emission wavelength is at least one wavelength selected from 380 nm to 10 nm;
the p-type semiconductor layer has a first p-type contact layer and a second p-type contact layer;
the first p-type contact layer is disposed between the second p-type contact layer and the light-emitting layer;
the first p-type contact layer is a p-type AlGaN layer;
the second p-type contact layer is a p-type AlGaN layer;
Al composition in the first p-type contact layer is continuously and monotonously decreased with distance from the light-emitting layer;
Al composition in the second p-type contact layer is continuously and monotonously decreased from value of Al composition at an interface between the first p-type contact layer and the second p-type contact layer with distance from the first p-type contact layer;
and
absolute value of Al composition decrease rate at any position in the second p-type contact layer is larger than absolute value of Al composition decrease rate at any position in the first p-type contact layer.

2. The Group III nitride semiconductor light-emitting device according to claim 1 , wherein
Mg doping concentration in the first p-type contact layer is continuously and monotonously increased with distance from the light-emitting layer;
Mg doping concentration in the second p-type contact layer is continuously and monotonously increased from value of Mg doping concentration at an interface between the first p-type contact layer and the second p-type contact layer with distance from the first p-type contact layer;
and
Mg doping concentration increase rate at any position in the second p-type contact layer is larger than an Mg doping concentration increase rate at any position in the first p-type contact layer.

3. The Group III nitride semiconductor light-emitting device according to claim 2 , wherein a thickness of the second p-type contact layer is smaller than a thickness of the first p-type contact layer.

4. The Group III nitride semiconductor light-emitting device according to claim 2 , wherein a thickness of the second p-type contact layer is any value in a range from 5 nm to 50 nm.

5. The Group III nitride semiconductor light-emitting device according to claim 2 , wherein the device further comprises a transparent electrode on the second p-type contact layer,
wherein the second p-type contact layer has a contact surface in contact with the transparent electrode, and
wherein the Al composition in the contact surface is 0 to 0.01.

6. The Group III nitride semiconductor light-emitting device according to claim 2 , wherein the absolute value of Al composition decrease rate in the first p-type contact layer is any value selected in a range from 2×10 −3 /nm to 8×10 −3 /nm, and the absolute value of Al composition decrease rate in the second p-type contact layer is any value selected in a range from 8×10 −3 /nm to 8×10 −2 /nm.

7. The Group III nitride semiconductor light-emitting device according to claim 1 , wherein a thickness of the second p-type contact layer is smaller than a thickness of the first p-type contact layer.

8. The Group III nitride semiconductor light-emitting device according to claim 7 , wherein the thickness of the second p-type contact layer is any value in a range from 5 nm to 50 nm.

9. The Group III nitride semiconductor light-emitting device according to claim 7 , wherein the device further comprises a transparent electrode on the second p-type contact layer,
wherein the second p-type contact layer has a contact surface in contact with the transparent electrode, and
wherein the Al composition in the contact surface is 0 to 0.01.

10. The Group III nitride semiconductor light-emitting device according to claim 1 , wherein a thickness of the second p-type contact layer is any value within a range from 5 nm to 50 nm.

11. The Group III nitride semiconductor light-emitting device according to claim 10 , wherein the device further comprises a transparent electrode on the second p-type contact layer,
wherein the second p-type contact layer has a contact surface in contact with the transparent electrode, and
wherein the Al composition in the contact surface is 0 to 0.01.

12. The Group III nitride semiconductor light-emitting device according to claim 1 , wherein the device further comprises a transparent electrode on the second p-type contact layer,
wherein the second p-type contact layer has a contact surface in contact with the transparent electrode, and
wherein the Al composition in the contact surface is 0 to 0.01.

13. The Group III nitride semiconductor light-emitting device according to claim 1 , wherein the absolute value of Al composition decrease rate in the first p-type contact layer is any value selected in a range from 2×10 −3 /nm to 8×10 −3 /nm.

14. The Group III nitride semiconductor light-emitting device according to claim 13 , wherein the absolute value of Al composition decrease rate in the second p-type contact layer is any value selected in a range from 8×10 −3 /nm to 8×10 −2 /nm.

15. The Group III nitride semiconductor light-emitting device according to claim 1 , wherein the absolute value of Al composition decrease rate in the second p-type contact layer is any value selected in a range from 8×10 −3 /nm to 8×10 −2 /nm.

Assignees

• Toyoda Gosei Kk
• Univ Meijo

Inventors

• Takeuchi Tetsuya
• Kamiyama Satoshi
• Iwaya Motoaki
• Akasaki Isamu
• Kojima Hisanori
• Yasuda Toshiki
• Iida Kazuyoshi

Classifications

• H10H20/8162

  Current-blocking structures · CPC title

• H10H20/01335

  the light-emitting regions comprising nitride materials · CPC title

• H10H20/833

  Transparent materials · CPC title

• H10H20/816

  having carrier transport control structures, e.g. highly-doped semiconductor layers or current-blocking structures · CPC title

• H10H20/815

  having stress relaxation structures, e.g. buffer layers · CPC title