Light-Emitting Diode With Non-Metallic Reflector

• US 20100038661A1
• Filed: 11/12/2008
• Published: 02/18/2010
• Est. Priority Date: 08/18/2008
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: TSMC Solid State Lighting Ltd. (Ennostar, Inc.)
• Inventors: Yu, Chen-Hua, Chen, Ding-Yuan, Chiou, Wen-Chih
• Granted Patent: US 8,525,200 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous

Abstract

A light-emitting diode (LED) device is provided. The LED device has a substrate, a reflective structure over the substrate, and an LED structure over the reflective structure. The reflective structure is formed of non-metallic materials. In one embodiment, the reflective structure is formed of alternating layers of different non-metallic materials having different refractive indices. In another embodiment, the reflective structure is formed of alternating layers of high-porosity silicon and low-porosity silicon. In yet another embodiment, the reflective structure is formed of silicon dioxide, which may allow the use of fewer layers. The reflective structure may be formed directly on the same substrate as the LED structure or formed on a separate substrate and then bonded to the LED structure.

Claims

1. A light-emitting diode (LED) device comprising:

a substrate;

a non-metallic reflective layer over a surface of the substrate; and

an LED structure formed on the non-metallic reflective layer.

2. The LED device of claim 1, wherein the non-metallic reflective layer comprises alternating layers of a first material and a second material, each of the first material and the second material being a non-metallic material.

3. The LED device of claim 1, wherein the non-metallic reflective layer comprises alternating layers of Si and SiC.

4. The LED device of claim 1, wherein the non-metallic reflective layer comprises alternating layers of Si and Si_xGe_1-x, Si and Si_xC_1-x, Si_xGe_1-x and Si_xC_1-x, or SiC and GaN.

5. The LED device of claim 1, wherein the non-metallic reflective layer comprises silicon dioxide.

6. The LED device of claim 1, wherein the non-metallic reflective layer comprises alternating layers of a high-porosity silicon and a low-porosity silicon.

7. The LED device of claim 1, wherein the non-metallic reflective layer comprises an omni-directional reflector.

8. A light-emitting diode (LED) device comprising:

a substrate;

a reflective structure on a first side of the substrate, the reflective structure comprising at least a first material and a second material, the first material and the second material having different refractive indices and being non-metallic; and

an LED structure formed on the reflective structure.

9. The LED device of claim 8, wherein the reflective structure comprises alternating layers of a high-porosity silicon and a low-porosity silicon.

10. The LED device of claim 9, wherein the LED device is a vertical LED device.

11. The LED device of claim 8, wherein the reflective structure comprises alternating layers of Si and Si_xGe_1-x, Si and Si_xC_1-x, Si_xGe_1-x and Si_xC_1-x, or SiC and GaN.

12. The LED device of claim 8, further comprising thermal vias extending through the reflective structure.

13. The LED device of claim 8, wherein the reflective structure comprises silicon dioxide.

14. A method of forming a light-emitting diode (LED), the method comprising:

providing a first substrate;

forming a reflective structure on the first substrate, the reflective structure being a non-metallic structure; and

forming an LED structure over the reflective structure.

15. The method of claim 14, wherein the forming the LED structure includes:

forming the LED structure on a second substrate;

bonding the LED structure to the reflective structure; and

removing the second substrate.

16. The method of claim 15, wherein the reflective structure comprises silicon dioxide.

17. The method of claim 14, wherein the forming the reflective structure comprises forming alternating layers of a first non-metallic layer and a second non-metallic layer.

18. The method of claim 14, wherein the forming the reflective structure comprises forming alternating layers of a high-porosity silicon and a low-porosity silicon.

19. The method of claim 14, wherein the reflective structure comprises an omni-directional reflector.

20. The method of claim 14, wherein the reflective structure comprises alternating layers of Si and Si_xGe_1-x, Si and Si_xC_1-x, Si_xGe_1-x and Si_xC_1-x, or SiC and GaN.