Micro light-emitting diode device

Patent metadata

Field	Value
Publication number	US-12439740-B2
Application number	US-202318182388-A
Country	US
Kind code	B2
Filing date	Mar 13, 2023
Priority date	Mar 13, 2023
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

A micro light-emitting diode device includes a substrate, a micro light-emitting diode, an isolation layer, and a cathode transparent electrode. The micro light-emitting diode is disposed on the substrate and includes a p-type III-nitride layer, n-type III-nitride layers with a layer number of m sequentially stacked above the p-type III-nitride layer, and an active layer between the p-type III-nitride layer and the n-type III-nitride layers. m is an integer greater than two. A top layer and a next layer in contact with each other of the n-type III-nitride layers contain aluminum. The isolation layer is on the substrate and surrounds the micro light-emitting diode. The cathode transparent electrode is at least partially in contact with a top surface of the top layer. A refractive index of the top layer is smaller than a refractive index of the next layer.

First claim

What is claimed is:

1. A micro light-emitting diode device, comprising:
a substrate having an anode electrode thereon;
a micro light-emitting diode having a lateral width smaller than 100 μm, disposed on and in contact with the anode electrode, and comprising:
a p-type III-nitride layer;
a plurality of n-type III-nitride layers with a layer number of m sequentially stacked above the p-type III-nitride layer, wherein m is an integer greater than two, and a top layer and a next layer in contact with each other of the n-type III-nitride layers contain aluminum; and
an active layer between the p-type III-nitride layer and a bottom layer of the n-type III-nitride layers;

an isolation layer on the substrate and surrounding the micro light-emitting diode; and
a cathode transparent electrode at least partially in contact with a top surface of the top layer of the n-type III-nitride layers,
wherein a refractive index of the top layer of the n-type III-nitride layers is smaller than a refractive index of the next layer of the n-type III-nitride layers.

2. The micro light-emitting diode device of claim 1 , wherein a height of the isolation layer relative to the substrate is equal to or smaller than a height of a top surface of the top layer to the substrate.

3. The micro light-emitting diode device of claim 2 , wherein a refractive index of the isolation layer is smaller than a refractive index of the cathode transparent electrode.

4. The micro light-emitting diode device of claim 2 , further comprising:
a dielectric layer between the isolation layer and a side surface of the micro light-emitting diode.

5. The micro light-emitting diode device of claim 1 , further comprising an encapsulation layer above and in contact with the cathode transparent electrode, wherein the cathode transparent electrode contains nano metal wires in contact with the top layer of the n-type III-nitride layers.

6. The micro light-emitting diode device of claim 1 , wherein the cathode transparent electrode is made of transparent conductive oxide, and a refractive index of the cathode transparent electrode is smaller than the refractive index of the top layer of the n-type III-nitride layers.

7. The micro light-emitting diode device of claim 1 , further comprising:
an MgO layer covering and in contact with the cathode transparent electrode, wherein a refractive index of the MgO layer is smaller than a refractive index of the cathode transparent electrode.

8. The micro light-emitting diode device of claim 1 , further comprising:
an encapsulation layer above and in contact with the cathode transparent electrode, wherein a refractive index of the encapsulation layer is smaller than a refractive index of the cathode transparent electrode.

9. The micro light-emitting diode device of claim 1 , wherein a height of the isolation layer relative to the substrate is greater than a height of a top surface of the top layer relative to the substrate.

10. The micro light-emitting diode device of claim 1 , wherein a thickness of each of the top layer and the next layer is greater than 40 nm.

11. The micro light-emitting diode device of claim 1 , wherein the bottom layer is an n-type GaN layer.

12. The micro light-emitting diode device of claim 1 , wherein the bottom layer contains aluminum, and an atomic ratio of aluminum of the bottom layer is smaller than an atomic ratio of aluminum of the top layer.

13. The micro light-emitting diode device of claim 1 , wherein an intermediate layer of the n-type III-nitride layers between the next layer and the bottom layer contains aluminum, and an atomic ratio of aluminum of the intermediate layer is smaller than an atomic ratio of aluminum of the next layer.

14. The micro light-emitting diode device of claim 1 , wherein the top layer and the next layer of the n-type III-nitride layers are n-type AlxGa1-xN layers.

15. The micro light-emitting diode device of claim 1 , wherein the n-type III-nitride layers except the bottom layer respectively have atomic ratios of aluminum that decrease in order from the top layer to an intermediate layer of the n-type III-nitride layers in contact with the bottom layer.

16. The micro light-emitting diode device of claim 15 , wherein the bottom layer contains aluminum, and an atomic ratio of aluminum of the bottom layer is smaller than the atomic ratio of aluminum of the intermediate layer.

17. The micro light-emitting diode device of claim 1 , wherein a total thickness of the n-type III-nitride layers is greater than a thickness of the p-type III-nitride layer.

18. The micro light-emitting diode device of claim 1 , wherein the anode electrode contains metal.

19. The micro light-emitting diode device of claim 18 , wherein the anode electrode contains Ag—Al alloys.

20. The micro light-emitting diode device of claim 18 , wherein the anode electrode contains nickel.

21. The micro light-emitting diode device of claim 1 , wherein a total thickness of the n-type III-nitride layers is greater than a sum of thicknesses of the active layer and the p-type III-nitride layer.

22. The micro light-emitting diode device of claim 1 , wherein a total thickness of the n-type III-nitride layers is greater than 0.5 μm.

23. The micro light-emitting diode device of claim 1 , further comprising:
another micro light-emitting diode disposed on the substrate, wherein the micro light-emitting diode and the another micro light-emitting diode are configured to emit lights of different wavelengths respectively; and
an isolation layer disposed on the substrate and surrounding the micro light-emitting diode and the another micro light-emitting diode.

24. The micro light-emitting diode device of claim 23 , wherein a distance between the micro light-emitting diode and the another micro light-emitting diode is less than 500 μm.

Assignees

• Mikro Mesa Tech Co Ltd

Inventors

• Chen Li-Yi
• Lee Hsin-Wei

Classifications

• H10H20/8312

  extending at least partially through the bodies · CPC title

• H10H20/853

  characterised by their shape · CPC title

• H10H20/833 Primary

  Transparent materials · CPC title

• H10H20/825 Primary

  containing nitrogen, e.g. GaN · CPC title

• H10H20/832

  characterised by their material · CPC title