Light emitting device having a patterned substrate and the method thereof
This disclosure provides a light-emitting device including a patterned substrate and the manufacturing method thereof. The patterned substrate has a plurality of depressions and/or extrusions for scattering light emitted from a light-emitting layer. Each of the plurality of depressions and/or extrusions comprises a top portion, a bottom portion, and a sidewall portion enclosing the top portion and the bottom portion, and at least part of the sidewall portion comprises a curve. In a preferred embodiment, the light-emitting device further comprises a rough surface formed on at least one of the top portion, the bottom portion, and the sidewall portion.
1. A light-emitting device, comprising
a patterned substrate having an uneven surface composed of a plurality of depressions and/or extrusions;
a light-emitting stack overlaying the patterned substrate, comprising a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer,
wherein at least one of the plurality of depressions and/or extrusions comprises a top portion, a bottom portion, and a sidewall portion, and at least part of the sidewall portion comprises a curve, and
wherein said top portion is substantially parallel to said bottom portion and includes a rough surface.
2. The light-emitting device according to claim 1 , wherein the sidewall portion comprises a plurality of symmetric planes.
3. The light-emitting device according to claim 1 , wherein at least one of the top portion and the bottom portion comprises a flat plane.
4. The light-emitting device according to claim 1 , wherein the substrate comprises sapphire.
5. The light-emitting device according to claim 4 , wherein the bottom portion comprises a sapphire C plane.
6. The light-emitting device according to claim 4 , wherein the sidewall portion comprises at least three symmetric sapphire R planes.
7. The light-emitting device according to claim 1 , wherein the top-view pattern of the depression and/or extrusion comprises circle or ellipse.
8. The light-emitting device according to claim 1 , wherein the light-emitting stack comprises a III-nitride compound.
9. The light-emitting device according to claim 1 , wherein the rough surface comprises a regular pattern or an irregular pattern.
10. A light-emitting device, comprising
a patterned substrate having an uneven surface composed of a plurality of depressions and/or extrusions;
a light-emitting stack overlaying the patterned substrate, comprising a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, wherein at least one of the plurality of depressions and/or extrusions comprises a top portion, a bottom portion, and
wherein said top portion is substantially parallel to said bottom portion and includes a rough surface.
11. The light-emitting device according to claim 10 , wherein the rough surface comprises a regular pattern or an irregular pattern.
12. The light-emitting device according to claim 10 , wherein at least part of the sidewall portion comprises a curve.
13. The light-emitting device according to claim 10 , wherein the sidewall portion comprises a plurality of symmetric planes.
14. The light-emitting device according to claim 10 , wherein the substrate comprises sapphire.
15. The light-emitting device according to claim 14 , wherein the bottom portion comprises a sapphire C plane.
16. The light-emitting device according to claim 14 , wherein the sidewall portion comprises at least three symmetric sapphire R planes.
17. The light-emitting device according to claim 10 , wherein the top-view pattern of the depression and/or extrusion comprises circle or ellipse.
18. The light-emitting device according to claim 10 , wherein the light-emitting stack comprises a III-nitride compound.