Light-emitting diode with non-metallic reflector

1. A light-emitting diode (LED) device comprising: a substrate; a non-metallic reflective layer over a surface of the substrate, the non-metallic reflective

layer being conductive and comprising alternating layers of Si x Ge 1-x and Si x C 1-x ; a plurality of thermally-conductive vias extending through the non-metallic reflective layer; a metal layer disposed over the non-metallic reflective layer; and an LED structure disposed over the metal layer, the LED structure being coupled to the non-metallic reflective layer through the metal 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 metal layer has a conductivity type the same as an upper layer of the LED structure.

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

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

6. 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, wherein the reflective structure comprises alternating layers of about 95% porosity silicon and about 30% porosity silicon;

a metal layer disposed over the reflective structure; and

an LED structure formed over the metal layer;

wherein:

the LED structure includes an active layer disposed between a first semiconductor layer and a second semiconductor layer, the first and second semiconductor layers having different types of conductivity; and

the reflective structure is configured to have a same type of conductivity as one of the first and second semiconductor layers disposed closer to the reflective structure.

7. The LED device of claim 6 , wherein the LED device is a vertical LED device.

8. The LED device of claim 6 , further comprising thermal vias extending through the reflective structure.

9. The LED device of claim 6 , wherein the reflective structure comprises silicon dioxide.

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

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

forming an LED structure on a second substrate;

forming a metal layer over the LED structure;

bonding the metal layer to the reflective structure using a thermally conductive material other than an oxide; and

removing the second substrate.

11. The method of claim 10 , wherein the reflective structure comprises silicon dioxide.

12. The method of claim 10 , wherein the forming the reflective structure comprises forming alternating layers of a first non-metallic layer and a second non-metallic layer.

13. The method of claim 10 , wherein the forming the reflective structure comprises forming alternating layers of a high-porosity silicon and a low-porosity silicon.

14. The method of claim 10 , wherein the reflective structure comprises an omni-directional reflector.

15. The method of claim 10 , wherein the reflective structure comprises alternating layers of Si and Si x Ge 1-x , Si and Si x Ge 1-x , and Si x C 1-x , or SiC and GaN.

16. The method of claim 10 , wherein the thermally conductive material comprises Au, Ni, or Cu.