Light emitting device, light emitting device package and lighting system

1. A light emitting device comprising:

a light emitting structure including a first conductive type semiconductor layer, an active layer over the first conductive type semiconductor layer, and a second conductive type semiconductor layer over the active layer;

a plurality of dielectric layers, one each formed in a plurality of cavities, respectively, the plurality of cavities formed in the light emitting structure;

a first electrode over the first conductive type semiconductor layer; and

a second electrode layer below the dielectric layers,

wherein the second electrode comprises a protruding portion extending into the light emitting structure and the protruding portion is in each of the plurality of cavities,

wherein a substantially central portion of the protruding portion spatially overlaps with a substantially central portion of the first electrode, and

wherein at least one of the plurality of dielectric layers spatially overlaps with both the substantially central portion of the protruding portion and the substantially central portion of the first electrode,

wherein the at least one of the plurality of dielectric layers is interdisposed between the substantially central portion of the protruding portion and the substantially central portion of the first electrode.

2. The light emitting device of claim 1 , wherein the plurality of cavities are defined by partially and sequentially removing the second conductive type semiconductor layer and the active layer until a portion of the first conductive type semiconductor is exposed.

3. The light emitting device of claim 1 , wherein the second electrode layer comprises:

a reflective layer over the dielectric layer; and

a conductive substrate over the reflective layer.

4. The light emitting device of claim 1 , wherein the first electrode spatially overlaps a portion of one cavity of the plurality of cavities.

5. The light emitting device of claim 1 , wherein in a constant voltage, current flows into the active layer to emit light, and in an electrostatic discharging, some of the current flows into the dielectric layer.

6. The light emitting device of claim 1 , wherein the substantially central portion of the protruding portion contacts a bottom surface of the at least one of the plurality of dielectric layers.

7. The light emitting device of claim 1 , wherein the plurality of dielectric layers comprise:

a first dielectric layer on an upper surface of the protruding portion; and

a second dielectric layer on a side surface of the protruding portion,

wherein the first dielectric layer is interdisposed between the substantially central portion of the protruding portion and the substantially central portion of the first electrode, and

the first dielectric layer is thicker than the second dielectric layer.

8. The light emitting device of claim 1 , wherein the plurality of cavities comprise a rectangular shape cross section.

9. A light emitting device comprising:

a light emitting structure including a first conductive type semiconductor layer, and a second conductive type semiconductor layer over the active layer;

a plurality of capacitors each on a plurality of cavities, respectively, the plurality of cavities formed in the light emitting structure; and

a first electrode layer over the light emitting structure,

wherein the plurality of capacitors each comprise the first conductive type semiconductor layer, a dielectric layer over the respective cavity, and a second electrode layer below the dielectric layer;

wherein the second electrode comprises a protruding portion extending into the light emitting structure and the protruding portion is in each of the plurality of cavities,

wherein a substantially central portion of the protruding portion spatially overlaps with a substantially central portion of the first electrode, and

wherein at least one portion of the dielectric layer spatially overlaps with both the substantially central portion of the protruding portion and the substantially central portion of the first electrode,

wherein the at least one portion of the dielectric layer is interdisposed between the substantially central portion of the protruding portion and the substantially central portion of the first electrode.

10. The light emitting device of claim 9 , wherein the second electrode layer comprises:

a reflective layer over the dielectric layer; and

a conductive substrate over the reflective layer.

11. The light emitting device of claim 9 , wherein the first electrode spatially overlaps a portion of the plurality of cavities.

12. The light emitting device of claim 1 , wherein a lateral width of the first electrode is the same as or less than a lateral width of one of the plurality of cavities.

13. The light emitting device of claim 9 , wherein a lateral width of the first electrode is the same as or less than a lateral width of one of the plurality of cavities.

14. The light emitting device of claim 9 , wherein the substantially central portion of the protruding portion contacts a bottom surface of the dielectric layer.

15. The light emitting device of claim 9 , wherein the dielectric layer comprises:

a first dielectric layer on an upper surface of the protruding portion; and

a second dielectric layer on a side surface of the protruding portion,

wherein the first dielectric layer is interdisposed between the substantially central portion of the protruding portion and the substantially central portion of the first electrode, and

the first dielectric layer is thicker than the second dielectric layer.

16. The light emitting device of claim 9 , wherein the plurality of cavities comprise a rectangular shape cross section.