Light emitting diode having side reflection layer

1. A light emitting diode comprising:

a semiconductor stack comprising a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer interposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer;

an ohmic reflection layer electrically connected to the second conductivity type semiconductor layer;

a first bump pad and a second bump pad disposed under the ohmic reflection layer and electrically connected to the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, respectively;

a light exit surface having a roughened surface through which light generated from the active layer is emitted;

side surfaces defining the light exit surface, wherein the side surfaces are outer side surfaces of the semiconductor stack; and

a side reflection layer covering at least part of the side surfaces,

wherein the light exit surface is disposed over the first conductivity type semiconductor layer opposite to the ohmic reflection layer, all layers from the active layer to the light exit surface are formed of gallium nitride-based semiconductors, and a distance from the active layer to the light exit surface is 50 μm or more.

2. The light emitting diode according to claim 1 , wherein:

the side surfaces comprise a perpendicular side surface perpendicular to an upper surface of the first conductivity type semiconductor layer and an inclined side surface inclined with respect to the perpendicular side surface; and

the perpendicular side surface is closer to the light exit surface than the inclined side surface.

3. The light emitting diode according to claim 2 , wherein the side reflection layer covers the perpendicular side surface and the inclined side surface.

4. The light emitting diode according to claim 3 , wherein the light emitting diode comprises a mesa disposed on the first conductivity type semiconductor layer and comprising the active layer and the second conductivity type semiconductor layer, the mesa being spaced apart from the side surfaces, and the side reflection layer is disposed only on the side surfaces.

5. The light emitting diode according to claim 4 , further comprising:

a lower insulation layer covering the ohmic reflection layer, the lower insulation layer having a first opening exposing the first conductivity type semiconductor layer and a second opening exposing the ohmic reflection layer;

a first pad metal layer disposed on the lower insulation layer and electrically connected to the first conductivity type semiconductor layer through the first opening;

a second pad metal layer disposed on the lower insulation layer and electrically connected to the ohmic reflection layer through the second opening; and

an upper insulation layer covering the first pad metal layer and the second pad metal layer, the upper insulation layer having a first opening exposing the first pad metal layer and a second opening exposing the second pad metal layer,

wherein the first and second bump pads are disposed on the upper insulation layer and electrically connected to the first pad metal layer and the second pad metal layer through the first opening and the second opening of the upper insulation layer, respectively.

6. The light emitting diode according to claim 5 , wherein the mesa comprises a through-hole formed through the second conductivity type semiconductor layer and the active layer to expose the first conductivity type semiconductor layer, and the first pad metal layer is electrically connected to the first conductivity type semiconductor layer exposed through the through-hole.

7. The light emitting diode according to claim 6 , wherein the mesa further comprises an indented portion formed on side surfaces thereof to expose the first conductivity type semiconductor layer, and the first pad metal layer is electrically connected to the first conductivity type semiconductor layer exposed through the indented portion.

8. The light emitting diode according to claim 7 , wherein the mesa has corners each having a cut shape, and the first pad metal layer is electrically connected to the first conductivity type semiconductor layer near the corners of the mesa.

9. The light emitting diode according to claim 1 , further comprising an ohmic oxide layer disposed on the second conductivity type semiconductor layer around the ohmic reflection layer.

10. The light emitting diode according to claim 1 , further comprising a gallium nitride-based substrate disposed on the first conductivity type semiconductor layer,

wherein the light exit surface is formed on the gallium nitride-based substrate and the side reflection layer covers a side surface of the substrate and a side surface of the first conductivity type semiconductor layer.

11. The light emitting diode according to claim 1 , wherein the light emitting diode has a light viewing angle of 110 degrees or less.

12. A light emitting diode comprising:

a substrate comprising a light exit surface having a roughened surface and side surfaces;

a first conductivity type semiconductor layer disposed on the substrate;

a mesa disposed on the first conductivity type semiconductor layer and comprising an active layer and a second conductivity type semiconductor layer;

an ohmic reflection layer covering the second conductivity type semiconductor layer;

a lower insulation layer covering the ohmic reflection layer, the lower insulation layer having a first opening exposing the first conductivity type semiconductor layer and a second opening exposing the ohmic reflection layer;

a first pad metal layer disposed on the lower insulation layer and electrically connected to the first conductivity type semiconductor layer through the first opening;

a first bump pad electrically connected to the first pad metal layer;

a second bump pad electrically connected to the ohmic reflection layer; and

a side reflection layer covering the side surfaces of the substrate and a side surface of the second conductivity type semiconductor layer,

wherein the side reflection layer is spaced apart from the first pad metal layer in a lateral direction so as not to overlap the first pad metal layer.

13. The light emitting diode according to claim 12 , wherein the side reflection layer is disposed only on the side surfaces of the substrate and a side surface of the first conductivity type semiconductor layer.

14. The light emitting diode according to claim 13 , further comprising:

a second pad metal layer disposed on the lower insulation layer and electrically connected to the ohmic reflection layer through the second opening; and

an upper insulation layer covering the first pad metal layer and the second pad metal layer, the upper insulation layer having a first opening exposing the first pad metal layer and a second opening exposing the second pad metal layer,

wherein the second bump pad is connected to the second pad metal layer through the second opening of the upper insulation layer.

15. The light emitting diode according to claim 13 , wherein the side surfaces of the substrate comprise a perpendicular side surface perpendicular to the light exit surface and an inclined side surface inclined with respect to the perpendicular side surface, and the side reflection layer covers the perpendicular side surface and the inclined side surface.

16. The light emitting diode according to claim 15 , further comprising an insulation layer interposed between the inclined side surface and the side reflection layer.

17. The light emitting diode according to claim 12 , wherein one end of the side reflection layer is flush with or spaced apart from a surface of the first conductivity type semiconductor layer around the mesa.

18. The light emitting diode according to claim 12 , wherein the mesa comprises:

a through-hole formed through the second conductivity type semiconductor layer and the active layer to expose the first conductivity type semiconductor layer; and

an indented portion formed on side surfaces of the mesa and exposing the first conductivity type semiconductor layer,

wherein the first pad metal layer is electrically connected to the first conductivity type semiconductor layer exposed to the through-hole and the indented portion.

19. The light emitting diode according to claim 18 , wherein the first pad metal layer is electrically connected to the first conductivity type semiconductor layer near corners of the mesa.

20. The light emitting diode according to claim 12 , wherein the side reflection layer comprises a metal reflection layer or a distributed Bragg reflector.