Method of making light emitting diode

• US 20090029492A1
• Filed: 08/29/2008
• Published: 01/29/2009
• Est. Priority Date: 09/08/2003
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: Epistar Corporation (Ennostar, Inc.)
• Inventors: Tu, Chuan-Cheng, Wu, Jen-Chau, Huang, Pao-I
• Granted Patent: US 7,704,760 B2
• Time in Patent Office: Days
• US Class Current: 438/22
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers

Abstract

A method of making a light emitting diode (LED) is disclosed. The LED of the present invention comprises a semiconductor layer of a first polarity, an active layer, and a semiconductor layer of a second polarity stacked from bottom to up, wherein a stacked structure at least composed of the active layer and the semiconductor layer of the second polarity have a side with a wave-shape border in a top view of the LED and/or at least one valley, thereby increasing the efficiency of emitting the light to the outside of the LED.

Claims

1. A method of making a light-emitting diode (LED), comprising:

providing a semiconductor layer of a first polarity;

forming an active layer on the semiconductor layer of the first polarity; and

forming a semiconductor layer of a second polarity on the active layer,

wherein at least one side of a stacked structure at least composed of the active layer and the semiconductor layer of the second polarity comprises an irregular surface, and the irregular surface comprises a deformed dimension greater than an emitting wavelength of the LED for making light emitted from the active layer outside the LED, and

wherein a plurality of independent valleys extend from an upper surface of the semiconductor layer of the second polarity to the active layer.

2. The method of making the LED according to claim 1, further comprising providing a substrate before providing the semiconductor layer of the first polarity, wherein the semiconductor layer of the first polarity is located on the substrate, and the plurality of independent valleys further reach to an upper surface of the substrate.

3. The method of making the LED according to claim 1, wherein the semiconductor layer of the first polarity is made of GaN.

4. The method of making the LED according to claim 1, wherein the active layer is made of InGaN.

5. The method of making the LED according to claim 1, wherein the semiconductor layer of the second polarity is made of GaN.

6. The method of making the LED according to claim 1, wherein the irregular surface of the at least one side in the top view of the LED has a wave-shape border.

7. The method of making the LED according to claim 6, wherein the wave-shape border in the top view of the LED is selected from a group consisting of triangular wave-shape border, semicircular wave-shape border, and parabolic wave-shape border.

8. The method of making the LED according to claim 6, wherein the irregular surface is formed by reactive ion etching.

9. The method of making the LED according to claim 1, wherein the plurality of independent valleys have different shapes.

10. The method of making the LED according to claim 9, wherein the shapes are selected from a group consisting of triangular wave-shape border, semicircular wave-shape border, and parabolic wave-shape border.

11. The method of making the LED according to claim 1, wherein the plurality of independent valleys expose the at least one side of the stacked structure.

12. A method of making a LED, comprising:

providing a semiconductor layer of a first polarity;

forming an active layer on the semiconductor layer of the first polarity; and

forming a semiconductor layer of a second polarity on the active layer,

wherein at least one side of a stacked structure at least composed of the active layer and the semiconductor layer of the second polarity comprises an irregular surface for making light emitted from the active layer outside the LED, and

wherein a plurality of independent valleys penetrates the semiconductor layer of the second polarity.

13. The method of making the LED according to claim 12, wherein the plurality of independent valleys have different shapes.

14. The method of making the LED according to claim 13, wherein the shapes are selected from a group consisting of triangular wave-shape border, semicircular wave-shape border, and parabolic wave-shape border.

15. The method of making the LED according to claim 12, wherein the plurality of independent valleys expose the at least one side of the stacked structure.

27. The method of making the LED according to claim 14, wherein the plurality of independent valleys expose the at least one side of the stacked structure.

16. A method of making a LED, comprising:

providing a semiconductor layer of a first polarity;

forming an active layer on the semiconductor layer of the first polarity;

forming a semiconductor layer of a second polarity on the active layer; and

forming a plurality of independent valleys in the semiconductor layer of the second polarity,

wherein at least one side of a stacked structure at least composed of the active layer and the semiconductor layer of the second polarity comprises an irregular surface, and the irregular surface comprises a deformed dimension greater than an emitting wavelength of the LED for making light emitted from the active layer outside the LED.

17. The method of making the LED according to claim 16, the plurality of independent valleys further reach the active layer.

18. The method of making the LED according to claim 16, further comprising providing a substrate before providing the semiconductor layer of the first polarity, wherein the semiconductor layer of the first polarity is located on the substrate, and the plurality of independent valleys further reach the substrate.

19. The method of making the LED according to claim 16, wherein the semiconductor layer of the first polarity is made of GaN.

20. The method of making the LED according to claim 16, wherein the active layer is made of InGaN.

21. The method of making the LED according to claim 16, wherein the semiconductor layer of the second polarity is made of GaN.

22. The method of making the LED according to claim 16, wherein the irregular surface of the at least one side in the top view of the LED has a wave-shape border.

23. The method of making the LED according to claim 22, wherein the wave-shape border in the top view of the LED is selected from a group consisting of triangular wave-shape border, semicircular wave-shape border, and parabolic wave-shape border.

24. The method of making the LED according to claim 22, wherein the irregular surface is formed by reactive ion etching.

25. The method of making the LED according to claim 16, wherein the plurality of independent valleys have different shapes.

26. The method of making the LED according to claim 25, wherein the shapes are selected from a group consisting of triangular wave-shape border, semicircular wave-shape border, and parabolic wave-shape border.