High output light emitting diode and method for fabricating the same

• US 20060145174A1
• Filed: 12/28/2005
• Published: 07/06/2006
• Est. Priority Date: 12/31/2004
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Hyun Jae, Ha, Jun Seok
• Granted Patent: US 7,939,841 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A high output light emitting diode (LED) and a method for fabricating the LED is disclosed. The LED includes a sidewall or surface that is inclined. A reflective film is formed on the inclined sidewall or surface to allow light to reflect from the reflective film and to emit the light upward or in a favorable direction with respect to the device, thereby being configured and enabled to improve a light output of the LED and dispense with an additional passivation process.

Claims

1. A high output light emitting diode (LED) comprising:

a structure having an inclined surface that includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer; and

a reflective film disposed along substantially all of the inclined surface to reflect light emitted from the active layer;

wherein the N-type semiconductor layer, the active layer, and the P-type semiconductor layer are provided in a stack, said stack being configured to allow light to be emitted from the active layer.

2. The LED as defined in claim 1, further comprising an angle defined by the inclined sidewall, the angle being in a range of 30˜

70 degrees.

3. The LED as defined in claim 1, wherein the reflective film comprises an anti-reflection (AR) film, a film stacked with reflective layers, or a high-reflection (HR) film.

4. A high output light emitting diode (LED) comprising:

a stack including an N-type semiconductor layer, an active layer, and a P-type semiconductor layer, said stack including mesa-etched sidewalls from the P-type semiconductor layer to portions of the N-type semiconductor layer, wherein the mesa-etched sidewalls and sidewalls of the active layer are inclined;

a reflective film disposed along the inclined sidewalls;

an N electrode being disposed on the N-type semiconductor layer,

a P electrode being disposed on the P-type semiconductor layer; and

a substrate attached to the stack.

5. The LED as defined in claim 4, wherein the inclined sidewalls comprise indents.

6. A high output LED comprises:

a structure including an active layer, an N-type semiconductor layer, and a P-type semiconductor layer, wherein the P-type semiconductor layer, the active layer and the N-type semiconductor layer include inclined sidewalls;

reflective films being disposed along the inclined sidewalls; and

an N electrode being disposed on the N-type semiconductor layer.

7. The LED as defined in claim 6, wherein the inclined sidewalls comprise indents.

8. The LED as defined in claim 7, wherein the indents comprise planar portions and curved portions.

9. The LED as defined in claim 6, wherein the P-type semiconductor layer, the active layer and the N-type semiconductor layer are configured in a stack such that a diameter of the P-type semiconductor layer is smaller than a diameter of the N-type semiconductor layer.

10. A method for fabricating a high output LED comprising:

stacking an N-type semiconductor layer, an active layer and a P-type semiconductor layer on a substrate;

mesa-etching sidewalls to be inclined from the P-type semiconductor layer to portions of the N-type semiconductor layer;

etching remaining sidewalls of the N-type semiconductor, the active layer, and the P-type semiconductor layer except for the mesa-etched sidewalls to be inclined;

evaporating reflective films on the inclined sidewalls; and

forming an N electrode on the mesa-etched N-type semiconductor layer, and forming a P electrode on the P-type semiconductor layer.

11. The method as defined in claim 10, wherein an inclination of the inclined sidewalls is in a range of 30˜

70 degrees.

12. The method as defined in claim 10, wherein the reflective film is an ant-reflection (AR) film, a film stacked with reflective layers, or a high-reflection (HR) film.

13. A method for fabricating a high output LED comprising:

stacking an N-type semiconductor layer, an active layer and a P-type semiconductor layer on a substrate;

etching sidewalls from the P-type semiconductor layer to portions of the N-type semiconductor layer;

forming an inclination on the etched sidewalls;

detaching the substrate from the N-type semiconductor layer;

forming a reflecting P electrode under the P-type semiconductor layer; and

forming a reflective film on the inclined sidewalls and forming an N electrode on the N-type semiconductor layer.

14. The method as defined in claim 13, wherein the inclination is in a range of 30˜

70 degrees.

15. The method as defined in claim 13, wherein the reflective film is an anti-reflection (AR) film, a film stacked with reflective layers, or a high-reflection (HR) film.

16. A method for fabricating a high output LED comprising:

stacking an N-type semiconductor layer, an active layer and a P-type semiconductor layer on a substrate;

forming a mask layer with a curvature on a sidewall of an upper surface of the P-type semiconductor layer;

masking the P-type semiconductor with the mask layer and etching from the P-type semiconductor layer to the N-type semiconductor layer to create inclinations and indents on sidewalls of the stack;

detaching the substrate from the N-type semiconductor layer;

forming a reflecting P electrode under the P-type semiconductor layer;

forming a reflective film on the inclined sidewalls; and

forming an N electrode on the N-type semiconductor layer.

17. The method as defined in claim 16, wherein the mask layer includes a marginal sidewall with indents comprising planar or curved portions.

18. A method for fabricating a high output LED comprising:

stacking an N-type semiconductor layer, an active layer, and a P-type semiconductor layer on a substrate;

forming a plurality of disc-shaped mask layers on the P-type semiconductor layer, each disc-shaped mask layer being spaced a predetermined distance apart;

masking the P-type semiconductor layer by the plurality of mask layers and etching from the P-type semiconductor layer to the N-type semiconductor layer to create an inclination on sidewalls of the stack;

detaching the substrate from the N-type semiconductor layer to obtain a plurality of light emitting structures that includes the P-type semiconductor layer, the active layer and the N-type semiconductor layer;

forming reflective films on side surfaces of the light emitting structures;

forming N electrodes adjacent to each N-type semiconductor layer of the light emitting structures; and

forming P electrodes adjacent to each P-type semiconductor layer of the light emitting structures.

19. The method as defined in claim 18, wherein the light emitting structure comprises a diameter of the P-type semiconductor layer that is smaller than a diameter of the N-type semiconductor layer.