UV LED with tunnel-injection layer

Patent metadata

Field	Value
Publication number	US-9705030-B2
Application number	US-201313865325-A
Country	US
Kind code	B2
Filing date	Apr 18, 2013
Priority date	Apr 18, 2012
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

An ultraviolet (UV) light emitting structure, a UV light emitting device, and a method of making a UV light emitting structure or device, wherein the UV light emitting structure or device has an AlN or AlGaN injection layer with high aluminum content between the light emitting active region and the p-doped layers and wherein the injection layer has a thickness such that holes can tunnel from the p-side of the semiconductor-based ultraviolet light emitting diode structure through the injection layer in the active zone and also reducing leakage electrons out of the active zone.

First claim

What is claimed is:

1. A semiconductor-based ultraviolet light emitting diode structure without an Mg-doped electron blocking layer comprising:
a light emitting active region comprising at least one quantum well layer sandwiched between quantum barrier layers;
a p-doped AlGaN superlattice;
one or more additional p-doped layers;
an AlN or AlGaN injection layer with high aluminum mole fraction between the light emitting active region and the p-doped layer, wherein said AlN or AlGaN injection layer has higher aluminum mole fraction than said quantum barrier layers and a bandgap energy larger than that of said quantum barrier layers,
wherein said AlN or AlGaN injection layer has higher aluminum mole fraction than aluminum mole fraction in each of said one or more additional p-doped layers and an average aluminum mole fraction of said p-doped AlGaN superlattice, and
wherein said AlN or AlGaN injection layer has Al concentration of more than 60%;
wherein said injection layer has a thickness such that holes can tunnel from the p-side of the semiconductor-based ultraviolet light emitting diode structure through the injection layer in the active zone and also reducing leakage electrons out of the active zone, wherein said semiconductor-based ultraviolet light emitting diode structure does not have an Mg-doped electron blocking layer.

2. The semiconductor-based ultraviolet light emitting diode structure of claim 1 , wherein said light emitting active region comprises AlGaN or InAlGaN quantum barriers, and wherein the aluminum mole fraction of the AlN or AlGaN tunnel injector layer is higher than the aluminum mole fraction of the quantum barriers.

3. The semiconductor-based ultraviolet light emitting diode structure of claim 1 , wherein said light emitting active region comprises quantum barriers, wherein one or more of said p-doped layers comprise aluminum, and wherein the aluminum mole fraction of the p-doped layers is lower than aluminum mole fraction of the quantum barriers.

4. The semiconductor-based ultraviolet light emitting diode structure of claim 1 , wherein said light emitting active region comprises quantum barriers, wherein one or more of said p-doped layers comprise aluminum, and wherein the aluminum mole fraction of the p-doped layers is equal to or higher than aluminum mole fraction of the quantum barriers.

5. The semiconductor-based ultraviolet light emitting diode structure of claim 1 , wherein said thickness of said injection layer is between about 1 nm and about 8 nm.

6. The semiconductor-based ultraviolet light emitting diode structure of claim 1 , wherein the active layer has a thickness of about 1 nm to about 1000 nm.

7. The semiconductor-based ultraviolet light emitting diode structure of claim 1 , wherein said one or more p-doped layer independently has a thickness of about 10 nm to about 1000 nm.

8. The semiconductor-based ultraviolet light emitting diode structure of claim 1 , wherein the active layer is doped with an impurity.

9. The semiconductor-based ultraviolet light emitting diode structure of claim 1 , wherein the injection layer is doped with an impurity.

10. The semiconductor-based ultraviolet light emitting diode structure of claim 9 , wherein the impurity is present in an amount less than 10 18 cm −3 .

11. The semiconductor-based ultraviolet light emitting diode structure of claim 9 , wherein the injection layer is doped with at least one impurity selected from the group consisting of silicon, oxygen, magnesium, beryllium, germanium and carbon.

12. The semiconductor-based ultraviolet light emitting diode structure of claim 1 , further comprising one or more n-doped semiconductor layers.

13. A semiconductor-based ultraviolet light emitting diode device comprising:
a substrate, and
the semiconductor-based ultraviolet light emitting diode of claim 1 .

14. The semiconductor-based ultraviolet light emitting diode structure of claim 1 , wherein said structure has layers stacked on a substrate in the following order above the substrate:
a n-doped semiconductor layer;
a light emitting active region;
an AlN or AlGaN injection layer with high aluminum mole fraction between the light emitting active region and the p-doped layer, wherein said injection layer has a thickness such that holes can tunnel from the p-side of the semiconductor-based ultraviolet light emitting diode structure through the injection layer in the active zone and also reducing leakage electrons out of the active zone;
an electron barrier layer; and
one or more p-doped layers.

15. A semiconductor-based ultraviolet light emitting diode device comprising:
a substrate, and
the semiconductor-based ultraviolet light emitting diode of claim 14 .

16. The semiconductor-based ultraviolet light emitting diode structure of claim 14 , wherein said n-doped semiconductor layer has a thickness between about 100 nm and about 10000 nm.

17. The semiconductor-based ultraviolet light emitting diode structure of claim 14 , wherein said electron barrier layer has a thickness between about 5 nm and about 100 nm.

18. The semiconductor-based ultraviolet light emitting diode structure of claim 14 , wherein said substrate is sapphire, Si, SiC, AlN, AlGaN, or a combination thereof.

19. The semiconductor-based ultraviolet light emitting diode device of claim 15 , wherein said device emits light having a wavelength between about 200 nm and about 300 nm.

20. The semiconductor-based ultraviolet light emitting diode device of claim 15 , wherein said device has a lifetime of from about 1 hour to about 10 6 hours.

21. The semiconductor-based ultraviolet light emitting diode device of claim 1 , wherein the light emitting active region comprises at least one AlGaN or InAlGaN quantum well layer sandwiched between two or more AlGaN and/or InAlGaN quantum barrier layers.

22. The semiconductor-based ultraviolet light emitting diode device of claim 21 , wherein said one or more quantum well layer is between about 0.5 nm and about 20 nm thick.

23. The semiconductor-based ultraviolet light emitting diode device of claim 22 , wherein and the thickness of said two or more quantum barrier layers is independently between about 0.5 nm and about 50 nm.

24. A method of producing a LED device having increased quantum efficiency in the deep UV (DUV) region and simultaneous reduced parasitic luminescence comprising:
forming a semiconductor-based ultraviolet light emitting diode structure comprising:
a light emitting active region comprising at least one quantum well layer sandwiched between quantum barrier layers,
a p-doped AlGaN superlattice;
one or more additional p-doped layers,
an AlN or AlGaN injection layer with high aluminum mole fraction between the light emitting active region and the p-doped layer, wherein said AlN or AlGaN injection layer has higher aluminum mole fraction than said quantum barrier layers and a bandgap energy larger than that of said quantum barrier layers, wherein said AlN or AlGaN injection layer has higher aluminum mole fraction than aluminum mole fraction in each of said one or more additional p-doped layers and an average aluminum mole fraction of said p-doped AlGaN superlattice, wherein said AlN or AlGaN injection layer has Al concentration of more than 60%; and wherein said injection layer has a thickness such that holes can tunnel from the p-side of the semiconductor-based ultraviolet light emitting diode structure through the injection layer in th

Assignees

• Univ Berlin Tech
• Forschungsverbund E V
• Univ Berlin Tech

Inventors

• Kneissl Michael
• Kolbe Tim

Classifications

• H01L33/32

  Electricity · mapped topic

• H01L33/06 Primary

  Electricity · mapped topic

• H10H20/825

  containing nitrogen, e.g. GaN · CPC title

• H10H20/812 Primary

  within the light-emitting regions, e.g. having quantum confinement structures · CPC title