Semiconductor light-emitting device and method for fabricating the same

• US 20070023763A1
• Filed: 07/25/2006
• Published: 02/01/2007
• Est. Priority Date: 07/27/2005
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Koike, Susumu, Ueda, Daisuke, Takigawa, Shinichi
• Granted Patent: US 7,439,552 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/38 with a particular shape

Abstract

A semiconductor light-emitting device includes a light-emitting layer and a light extraction layer formed on the light-emitting layer and made of a resin material containing particles. The maximum size of each of the particles contained in the light extraction layer is smaller than the wavelength of emitted light penetrating through the light extraction layer.

Claims

1. A semiconductor light-emitting device comprising:

a light-emitting layer; and

a light extraction layer formed on the light-emitting layer and containing particles,

the maximum size of each said particle being smaller than the wavelength of emitted light penetrating through the light extraction layer.

2. The semiconductor light-emitting device of claim 1, wherein

the refractive index of each said particle for the emitted light is larger than that of the light extraction layer for the emitted light.

3. The semiconductor light-emitting device of claim 1, wherein

the light extraction layer is formed at its top surface with corrugations.

4. The semiconductor light-emitting device of claim 3, wherein

the corrugations are of a periodic structure.

5. The semiconductor light-emitting device of claim 1, wherein

the light extraction layer is added with the particles such that the density of the particles is gradually decreased in a direction of emission of the emitted light.

6. The semiconductor light-emitting device of claim 5, wherein

the light extraction layer includes a first layer and a second layer sequentially formed on the light-emitting layer, and

the amount of ones of the particles with which the second layer is added is smaller than that of ones of the particles with which the first layer is added.

7. The semiconductor light-emitting device of claim 1 further comprising:

an electrode for injecting carriers into the light-emitting layer; and

a wire connected to the electrode,

an end surface of the light extraction layer being apart from the electrode and the wire.

8. The semiconductor light-emitting device of claim 1, wherein

the light extraction layer is formed to cover top and side surfaces of the light-emitting layer.

9. A semiconductor light-emitting device comprising:

a semiconductor layered structure obtained by stacking a plurality of semiconductor layers including a light-emitting layer; and

a light extraction layer made of a resin material formed on the top surface of at least one part of the semiconductor layered structure,

said resin material containing particles,

the refractive index of each said particle for emitted light being larger than that of the resin material for the emitted light, and

the size of each said particle being smaller than the wavelength of the emitted light penetrating through the resin material.

10. The semiconductor light-emitting device of claim 9, wherein

the light extraction layer is formed at its top surface with corrugations.

11. The semiconductor light-emitting device of claim 10, wherein

the corrugations are of a periodic structure.

12. The semiconductor light-emitting device of claim 9, wherein

the light extraction layer is added with the particles such that the density of the particles is gradually decreased in a direction of emission of the emitted light.

13. The semiconductor light-emitting device of claim 12, wherein

the light extraction layer includes a first layer and a second layer sequentially formed on the semiconductor layered structure, and

the amount of ones of the particles with which the second layer is added is smaller than that of ones of the particles with which the first layer is added.

14. The semiconductor light-emitting device of claim 9 further comprising:

an electrode formed on the semiconductor layered structure to inject carriers into the light-emitting layer; and

a wire connected to the electrode,

an end surface of the light extraction layer being apart from the electrode and the wire.

15. The semiconductor light-emitting device of claim 9, wherein

the light extraction layer is formed to cover top and side surfaces of the light-emitting layer.

16. A method for fabricating a semiconductor light-emitting device, said method comprising the steps of:

(a) sequentially stacking a first semiconductor layer, a light-emitting layer and a second semiconductor layer on a wafer-level substrate, thereby forming a semiconductor layered structure;

(b) forming, on the semiconductor layered structure, a light extraction layer made of a resin material containing particles;

(c) selectively removing a portion of the light extraction layer located on a first electrode formation region of the second semiconductor layer, thereby exposing the first electrode formation region;

(d) forming a first electrode on the exposed first electrode formation region;

(e) selectively removing respective portions of the light extraction layer, the second semiconductor layer and the light-emitting layer located on a second electrode formation region of the first semiconductor layer, thereby exposing the second electrode formation region;

(f) forming a second electrode on the exposed second electrode formation region; and

(g) dividing, into chips, the wafer-level substrate on which the semiconductor layered structure formed with the light extraction layer, the first electrode and the second electrode is formed,

wherein the resin material has a first refractive index that is smaller than a second refractive index of the semiconductor layered structure for emitted light from the light-emitting layer, and

the particles are transparent to the emitted light, have a third refractive index that is larger than the first refractive index and have a smaller diameter than the wavelength of the emitted light penetrating through the resin material.

17. The method of claim 16, wherein

the step (b) includes the step of, after the formation of the resin material on the semiconductor layered structure and before curing of the formed resin material, pressing a die with corrugations against the top surface of the resin material and transferring the corrugations to the top surface of the resin material, thereby forming corrugations at the top surface of the light extraction layer.